Surface Of Head Research Articles

Performance of textured dual mobility total hip prosthesis with a concave dimple during Muslim prayer movements

The single mobility bearing as a previous bearing design of total hip prosthesis has severe mobility constraints that can result in dislocation during Muslim (people who follow the Islam as religion) prayer movements, specifically shalat that requires intense movement. There are five intense movements (i.e., bowing, prostration, sitting, transition from standing to prostration, and final sitting) during Muslim prayer that may generate an impingement problem for patients with total hip prosthesis. In this work, textured dual mobility total hip prosthesis with two textured cases (i.e., textured femoral head and textured inner liner) are presented and their performances are numerically evaluated against untextured surface model during Muslim prayer movement. The concave dimple design is chosen for surface texturing, while for simulating femoral head materials, SS 316L and CoCrMo is choosen. To represent the real condition, three-dimensional computational fluid dynamics (CFD) coupled with two-way fluid–structure interaction (FSI) methods are employed to analyze elastohydrodynamic lubrication problem with non-Newtonian synovial fluid model. The main aim of the present study is to investigate the tribological performance on dual mobility total hip prosthesis with applied textured surface with concave dimple in femoral head and inner liner surface under Muslim prayer movements. It is found that applying surface texturing has a beneficial effect on the lubrication performance for some intense movements. The textured femoral head model performs better than textured inner liner model and untextured model (both femoral head and inner liner). The numerical results also indicate superior performance of CoCrMo femoral head compared to SS 316L femoral head. These findings can be used as a reference for biomedical engineers and orthopedic surgeons in designing and choosing suitable total hip prosthesis for Muslims makes they can carry out Muslim prayer movements like humans in general who have normal hip joints.

Image segmentation method of rail head defects and area measurement of selected segments

The operation safety of railway transport, which is the most important economic and social factor, is largely determined by the technical condition of the rail track and measures to maintain the quality of its track management system. One of the system elements for ensuring the accident-free operation of the track is the technical diagnosis of rails using a method complex of non-destructive control of rails, such as acoustic (ultrasonic), magnetic, combined, etc., and monitoring of the track using methods of measuring the geometry of the rail track and its disturbances. When the wheel interacts with the rail, especially on high-speed and load-stressed sections, defects and damage inevitably occur in the rails. A rather large share of such defects are on the rolling surface of the rail head. Formed defects develop rapidly, which seriously complicates the safety of train traffic. Therefore, accurate and quick detection of defects on the rolling surface of the rail head is very important. However, it is quite difficult to detect defects on the rolling surface of the rail by the acoustic (ultrasound) method due to the violation of tight contact between the rolling surface of the rail head and the piezoelectric transducer. In this case, it is quite convenient to detect surface defects of the rail head using video control. The article provides a comparative analysis of segmentation methods. There has been presented the method of image segmentation of main rail defects based on general contour preparation and parallel-hierarchical (PH) transformation using their classification. The parallel-hierarchical transformation method allows to increase the segmentation accuracy of individual areas in the original image compared to similar ones. The algorithm of pyramidal generalized-contour preparation and the criterion system allows, by calculating the threshold for each level of the gray scale, to present the study of the image with the corresponding contour preparations at the segmentation level. Modeling of recursive generalized-contour preparation and PH transformation method for image segmentation problem of rail head defects shows that, compared to the segmentation method based on the increase of areas, the accuracy of image segmentation is better. A modified method of calculating the image contour area based on the coding of lines forming the boundaries of the black and white areas of the two-gradation image has been given.

The effect of the track plan on the damage to rails by contact fatigue crambling

An analysis of foreign and domestic experience in improving traffic safety while extending the service life of rails and improving their interaction with the wheels of rolling stock shows that the working conditions of rails are much more difficult in curved sections of the track, especially in the outer thread, due to the intense impact of the ridges of the wheels of rolling stock on the lateral working One of the reasons for the formation of contact fatigue stains on the lateral working surface of the rail head is the presence of tangential stresses that occur in the absence of perpendicular pressure of the wheel on the rail head. In addition, the movement of the wheels on the rails is accompanied by slippage, which appears due to the taper of the wheels and the occurrence of the wheel crest on the rail head. A typical case of the wheel crest running over the rail head is the movement of the crew along curved sections of the track. In this case, the guide axle runs over one of the wheels on the rail head. As a result, there is a transverse slip of the wheel on the rolling surface and friction forces between the wheel and the rail are appropriately oriented to the axes. These processes, enhanced by an increase in dynamic action, cause more intense damage to the rail heads by defects 11 in the curves, while defects mostly appear on the outer rail thread.

Construction of a predictive nomogram for functional recovery after Bernese periacetabular osteotomy.

Surgical indications for Bernese periacetabular osteotomy (PAO) are well-established. However, the extent of postoperative functional recovery varies widely, as observed in clinical follow-ups. Thus, preoperative evaluation is crucial. This study aims to identify factors that influence functional recovery post-PAO and to develop a predictive nomogram. Retrospective data were collected between December 2016 and March 2022 at The First Affiliated Hospital of Shandong First Medical University. The dataset included demographic and imaging data of patients who underwent PAO. The least absolute shrinkage and selection operator (LASSO) regression was utilized to identify influencing factors, which were further analyzed using multivariate logistic regression to construct a predictive nomogram for post-PAO functional recovery. The analysis identified critical factors affecting functional recovery post-PAO, namely, the preoperative distance from the innermost surface of the femoral head to the ilioischial line, the surgical approach, preoperative acetabular depth, and the continuity of the preoperative Calve line. A nomogram was developed using these significant predictors. The model's validity was demonstrated by the receiver operating characteristic curve, with an area under the curve of 0.864. Additionally, the calibration curve confirmed the nomogram's accuracy, showing a strong correlation between observed and predicted probabilities, indicating high predictive accuracy. This predictive nomogram effectively identifies patients most suitable for PAO, providing valuable guidance for selecting surgical candidates and determining the appropriate surgical approach.

Analysis of scooter engine piston damage

The causes of operational damage to the piston of a single-cylinder two-stroke internal combustion engine (ICE) of a scooter, made of a piston aluminum-silicon alloy by mold casting, were investigated. It was found that the AK21M2.5H2.5 type alloy has a dispersed eutectic structure (α+β-Si) with a small number of primary silicon crystals of a compact shape, the size of which does not exceed 10 μm. The porosity of the cast alloy of the piston is less than the lowest 1st porosity point, as well as the quality structure, could not be the cause of its damage. The average value of the microhardness measured on the surface of the piston head (70 HV0.98) is slightly less than the standardized hardness (90 НВ ÷ 100 НВ) of ingots after mold casting and artificial aging without preliminary hardening, which indirectly indicates overheating of the piston during operation. The detected damage to the outer surface of the piston in the form of deep scratches and worn stripes is not caused by metallurgical or technological factors, but by violations of operating conditions: overheating and lack of lubricant in the contact zone of the piston and cylinder.

Time-resolved Laser Speckle Contrast Imaging (TR-LSCI) of Cerebral Blood Flow.

To address many of the deficiencies in optical neuroimaging technologies, such as poor tempo-spatial resolution, low penetration depth, contact-based measurement, and time-consuming image reconstruction, a novel, noncontact, portable, time-resolved laser speckle contrast imaging (TR-LSCI) technique has been developed for continuous, fast, and high-resolution 2D mapping of cerebral blood flow (CBF) at different depths of the head. TR-LSCI illuminates the head with picosecond-pulsed, coherent, widefield near-infrared light and synchronizes a fast, high-resolution, gated single-photon avalanche diode camera to selectively collect diffuse photons with longer pathlengths through the head, thus improving the accuracy of CBF measurement in the deep brain. The reconstruction of a CBF map was dramatically expedited by incorporating convolution functions with parallel computations. The performance of TR-LSCI was evaluated using head-simulating phantoms with known properties and in-vivo rodents with varied hemodynamic challenges to the brain. TR-LSCI enabled mapping CBF variations at different depths with a sampling rate of up to 1 Hz and spatial resolutions ranging from tens/hundreds of micrometers on rodent head surfaces to 1-2 millimeters in deep brains. With additional improvements and validation in larger populations against established methods, we anticipate offering a noncontact, fast, high-resolution, portable, and affordable brain imager for fundamental neuroscience research in animals and for translational studies in humans.

Accurate tissue flap reconstruction method based on the quadratic surface developability for head and neck soft tissue defects

Soft tissue defects resulting from head and neck tumor resection seriously impact the physical appearance and psychological well-being of patients. The complex curvature of the human head and neck poses a formidable challenge for maxillofacial surgeons to achieve precise aesthetic and functional restoration after surgery. To this end, a normal head and neck volunteer was selected as the subject of investigation. Employing Gaussian curvature analysis, combined with mechanical constraints and principal curvature analysis methods of soft tissue clinical treatment, a precise developable/non-developable area partition map of the head and neck surface was obtained, and a non-developable surface was constructed. Subsequently, a digital design method was proposed for the repair of head and neck soft tissue defects, and an in vitro simulated surgery experiment was conducted. Clinical verification was performed on a patient with tonsil tumor, and the results demonstrated that digital technology-designed flaps improved the accuracy and aesthetic outcome of head and neck soft tissue defect repair surgery. This study validates the feasibility of digital precision repair technology for soft tissue defects after head and neck tumor resection, which effectively assists surgeons in achieving precise flap transplantation reconstruction and improves patients' postoperative satisfaction.

Manipulations with the Head of those Buried in the Bystrovka Necropolis (the Early Iron Age of the Upper Ob Region)

The article deals with analysis of the material from the Bystrovka necropolis (Bystrovka-1,2,3) of the Early Iron Age in the Upper Ob region. All these precedents were integrated into the context of various types of burial rites: inhumation, secondary burials, and ritual partial burials. On the surface of individual heads there are various traces of violent and industrial influences – stabbing, punching and cutting tools. In accordance with the shape of the holes from the piercing tools on the surface of some of the skulls from Bystrovka-2, kurgan-9, it can be determined that they were made with a chekhan with a subrectangular section. This type of impact weapon of the Early Iron Age is not widely represented in the north of the Upper Ob region. At the same time, most of the iron chasings of the Early Iron Age of the Upper Ob had a predominantly rounded cross-section of their striker. It should also be noted that the holes from the blows of the chekhan on the skull in Altai had a predominantly rounded section. Whereas, on the territory of the Middle Yenisei (Tagar culture), the holes from the chekhan of the coinage also had a predominantly sub-square section. Such a similarity of the entrance holes from the coinage on the Middle Yenisei and the Upper Ob (Bystrovka-2) indirectly indicates that the coinage with which the blows were struck could be of “Tagar” origin. Along with these features, it should be noted that, judging by the tracing features of striking with a coin on one of the skulls from Bystrovka-2 kurgan-9, it was struck on the head when the person was kneeling in front of the attacker. It is this pose that is shown on one of the petroglyphs on Mount Kunya in the Middle Yenisei. The presence of an extensive report of radiocarbon and dendrochronological dating for the Bystrovka necropolis makes it possible, along with various objects of the object complex (arrowheads, ceramic vessels, etc.), to date manipulations with the heads of those buried in the middle – the last third of the 1st millennium BC. In general, all these facts fit into the format of the “archeology of violence” and illustrate not only various variants of injuries from violent actions, but also complex and multi-stage rituals reflected in the funeral rites.

Towards a radiation free numerical modelling framework to predict spring assisted correction of scaphocephaly

Sagittal Craniosynostosis (SC) is a congenital craniofacial malformation, involving premature sagittal suture ossification; spring-assisted cranioplasty (SAC) – insertion of metallic distractors for skull reshaping – is an established method for treating SC. Surgical outcomes are predictable using numerical modelling, however published methods rely on computed tomography (CT) scans availability, which are not routinely performed. We investigated a simplified method, based on radiation-free 3D stereophotogrammetry scans. Eight SAC patients (age 5.1 ± 0.4 months) with preoperative CT and 3D stereophotogrammetry scans were included. Information on osteotomies, spring model and post-operative spring opening were recorded. For each patient, two preoperative models (PREOP) were created: i) CT model and ii) S model, created by processing patient specific 3D surface scans using population averaged skin and skull thickness and suture locations. Each model was imported into ANSYS Mechanical (Analysis System Inc., Canonsburg, PA) to simulate spring expansion. Spring expansion and cranial index (CI - skull width over length) at times equivalent to immediate postop (POSTOP) and follow up (FU) were extracted and compared with in-vivo measurements. Overall expansion patterns were very similar for the 2 models at both POSTOP and FU. Both models had comparable outcomes when predicting spring expansion. Spring induced CI increase was similar, with a difference of 1.2%±0.8% for POSTOP and 1.6%±0.6% for FU. This work shows that a simplified model created from the head surface shape yields acceptable results in terms of spring expansion prediction. Further modelling refinements will allow the use of this predictive tool during preoperative planning.

Characterization of the Age-Related Differences in Porcine Acetabulum and Femoral Head Articular Cartilage.

The use of porcine animal models for cartilage injury has increased recently due to their similarity with humans with regard to cartilage thickness, limited intrinsic healing of chondral defects, and joint loading biomechanics. However, variations in the mechanical and biochemical properties of porcine hip articular cartilage among various tissue ages and weightbearing (WB) regions are still unknown. This study's aim was to characterize the mechanical and biochemical properties of porcine hip articular cartilage across various ages and WB regions. Articular cartilage explants were harvested from WB and non-weightbearing (NWB) surfaces of the femoral head and acetabulum of domesticated pigs (Sus scrofa domesticus) at fetal (gestational age: 80 days), juvenile (6 months), and adult (2 years) ages. Explants underwent compressive stress-relaxation mechanical testing, biochemical analysis for total collagen and glycosaminoglycan (GAG) content, and histological staining. Juvenile animals consistently had the highest mechanical properties, with 2.2- to 7.6-time increases in relaxation modulus, 1.3- to 2.3-time increases in instantaneous modulus, and 4.1- to 14.2-time increases in viscosity compared with fetal cartilage. Mechanical properties did not significantly differ between the WB and NWB regions. Collagen content was highest in the NWB regions of the juvenile acetabulum (65.3%/dry weight [DW]) and femoral head (75.4%/DW) cartilages. GAG content was highest in the WB region of the juvenile acetabulum (23.7%/DW) and the WB region of the fetal femoral head (27.5%/DW) cartilages. Histological staining for GAG and total collagen content followed the trends from the quantitative biochemical assays. This study provides a benchmark for the development and validation of preclinical porcine models for hip cartilage pathologies.

The effects of peeling on finite element method -based EEG source reconstruction

The problem of reconstructing brain activity from electric potential measurements performed on the surface of a human head is not an easy task: not only is the inverse problem fundamentally ill-posed, but the methods utilized in constructing a synthetic forward solution themselves contain many inaccuracies. As an example the usual method of modelling primary currents in the human head via dipoles brings about at least two modelling errors: one from the singularity introduced by the dipole, and one from placing such dipoles near conductivity discontinuities in the active brain layer boundaries.In this article, we observe how the removal of possible source locations from the vicinity of active layer surfaces affects the localisation accuracy of two inverse methods, Standardized Low-Resolution Tomography (sLORETA) and Dipole Scan, at different signal-to-noise ratios (SNR), when the H(div) source model is used. This source location restriction is achieved by setting a peeling depth or a threshold distance dp, that acceptable source positions must have from active gray matter boundaries. Our aim is to understand the full effect and potential of peeling with a multi-compartment and high-resolution head model, in which the cortical activity is limited into a thin and strongly folded layer of gray matter.Our results suggest that peeling can significantly improve the overall regularity of the reconstructed distributions, when a suitable peeling depth and a low enough noise level are selected. The applied inverse algorithm and brain compartment under observation also affect the accuracy.

Finite element analysis for predicting osteonecrosis of the femoral head collapse based on the preserved angles

To establish finite element models of different preserved angles of osteonecrosis of the femoral head (ONFH) for the biomechanical analysis, and to provide mechanical evidence for predicting the risk of ONFH collapse with anterior preserved angle (APA) and lateral preserved angle (LPA). A healthy adult was selected as the study object, and the CT data of the left femoral head was acquired and imported into Mimics 21.0 software to reconstruct a complete proximal femur model and construct 3 models of necrotic area with equal volume and different morphology, all models were imported into Solidworks 2022 software to construct 21 finite element models of ONFH with LPA of 45°, 50°, 55°, 60°, 65°, 70°, and 75° when APA was 45°, respectively, and 21 finite element models of ONFH with APA of 45°, 50°, 55°, 60°, 65°, 70°, 75° when LPA was 45°, respectively. According to the physiological load condition of the femoral head, the distal femur was completely fixed, and a force with an angle of 25°, downward direction, and a magnitude of 3.5 times the subject's body mass was applied to the weight-bearing area of the femoral head surface. The maximum Von Mises stress of the surface of the femoral head and the necrotic area and the maximum displacement of the weight-bearing area of the femoral head were calculated and observed by Abaqus 2021 software. The finite element models of ONFH were basically consistent with biomechanics of ONFH. Under the same loading condition, there was stress concentration around the necrotic area in the 42 ONFH models with different preserved angles composed of 3 necrotic areas with equal volume and different morphology. When APA was 60°, the maximum Von Mises stress of the surface of the femoral head and the necrotic area and the maximum displacement of the weight-bearing area of the femoral head of the ONFH models with LPA<60° were significantly higher than those of the models with LPA≥60° ( P<0.05); there was no significant difference in each index among the ONFH models with LPA≥60° ( P>0.05). When LPA was 60°, each index of the ONFH models with APA<60° were significantly higher than those of the models with APA≥60° ( P<0.05); there was no significant difference in each index among the ONFH models with APA≥60° ( P>0.05). From the perspective of biomechanics, when a preserved angle of ONFH is less than its critical value, the stress concentration phenomenon in the femoral head is more pronounced, suggesting that the necrotic femoral head may have a higher risk of collapse in this state.

Two new species of Leptobrachella Smith 1925 (Amphibia: Megophryidae) from Cao Bang Province, Vietnam.

Two new species, Leptobrachella phiaoacensis sp. nov. and Leptobrachella phiadenensis sp. nov., are described from Phia Oac-Phia Den National Park, Cao Bang Province, Vietnam based on genetic divergence and morphological differences. Leptobrachella phiaoacensis sp. nov. is characterized by a combination of the following characters: size medium (27.833.3 mm in five adult males and 31.541.8 mm in five adult females); head longer than wide; tympanum distinct; dorsal skin shagreened with fine tubercles; toes webbing rudimentary, with narrow lateral fringes; supratympanic fold edged by a distinct black line; the presence of a dark brown triangle in interorbital region and a W-shaped marking in scapular region; belly from pinkish white to white with dark brown specking on belly periphery; iris bicolored copper in upper part, fading to silvery grey in lower part. Leptobrachella phiadenensis sp. nov. is distinguished from its congeners by a combination of the following morphological characters: size medium (27.628.6 mm in two adult females); head wider than long; tympanum distinct; skin on dorsal head and body rough with warts, tubercles and dermal ridges; toes webbing rudimentary, with narrow dermal fringes; supratympanic fold orange; dorsal surface of head and body with some large dark brown markings, a dark brown triangle in interorbital region, edged in white; flank light brown with some dark flecks; belly white with dark specking on outer margins; iris bicolored, copper in upper part, fading to silvery grey in lower part. In terms of genetic distance, the two new species differ from each other and other congeners for which comparable sequences are available by at least 3.7% (16S rRNA gene). Recognition of these new species brings the total number of known species in the genus Leptobrachella from Vietnam to 34.

Participation of WD repeat-containing protein 54 (WDR54) in rat sperm-oocyte fusion through interaction with both IZUMO1 and JUNO

Fertilization is a complex process that depends on the fusion of the cell membrane of sperm with that of oocyte, and it involves sperm-oocyte recognition, binding, and fusion, which are mediated by multiple proteins. Among those proteins, IZUMO1 and its receptor JUNO have been identified as essential factors for sperm-oocyte recognition and fusion. However, the interaction between IZUMO1 and JUNO alone does not lead to cell membrane fusion, suggesting the involvement of additional proteins in sperm-oocyte membrane fusion. In this study, we have discovered that a protein called WDR54, which consists of WD-repeat modules, is located on the cell membrane of sperm, as well as on the cell membrane and in the cytoplasm of the oocyte. We have found that WDR54 is involved in sperm-oocyte fertilization. When sperm and oocyte were treated with anti-WDR54 ascites, the in vitro fertilization (IVF) rate significantly decreased. Furthermore, our research has shown that WDR54 interacts with both IZUMO1 and JUNO, and it colocalizes with IZUMO1 on the surface of the sperm head and with JUNO on the oocyte surface. Through structural analysis of the putative complexes of WDR54-IZUMO1 and WDR54-JUNO, we infer that these three proteins could form a complex of JUNO-WDR54-IZUMO1-JUNO (referred to as the “JWIJ complex”) on the oocyte surface. Our findings suggest that WDR54 is an important factor involved in sperm-oocyte adhesion and fusion. This discovery provides new insight into the mechanisms of mammalian sperm-oocyte adhesion and fusion.

Mesoscopic analysis of drag reduction performance of bionic furrow opener based on the discrete element method.

In order to study the dynamic interface mechanical behavior between soil and agricultural machinery and reveal the causes of tillage resistance, three kinds of bionic furrow opener were designed according to the characteristics of earthworm head surface curve, using the discrete element method to simulate and analyze the process of the furrow openers. The results showed that the order of ditching resistance from large to small is traditional opener, bionic corrugated opener, bionic ridgeline opener, bionic composite opener. With the same ditching speed, the drag reduction effect of the three bionic openers increases with the increase of the ditching depth. During the process of increasing the depth from 30 mm to 60 mm and 90 mm, the ditching resistance of the traditional opener increased from 11.56 N to 28.32 N and 48.61 N as well as the maximum drag reduction ratio increased from 5.58% to 7.20% and 8.93% for the bionic composite opener. With the same ditching depth, the bionic composite opener reached the highest drag reduction rate of all bionic openers when the speed is 100 mm/s, the value is 9.08%. The width of the ditch of the three bionic openers is smaller than that of the traditional opener. Bionic corrugated opener can improve the ditch height and reduce the ditch width,the corrugated structure creates a gap between the surface of the core and the particles, reducing the number of contact and contact area of the particles. The number of contact particles of the three bionic openers is smaller than that of the traditional opener. The bionic composite opener has the smallest force field and the soil disturbance caused by the core share surface is small, the soil is evenly distributed along the core surface. The discrete element simulation shows that the bionic opener can effectively reduce the ditching resistance and improve the quality of ditching, which provides a theoretical basis for subsequent research and optimization.

Effects of flow conditions on the cavitation characteristics of viscous oil around a hydrofoil

Viscous oils, which are media commonly used for fluid power transmission, are characterized by high velocities, temperatures, and pressures when working in fluid components and mechanics. The transient nature of viscous oil makes it susceptible to complex operating conditions, which result in cavitation phenomena and can threaten the normal operation and safety of machinery and components. In this study, a three-dimensional computational fluid dynamics model that accounts for cavitation was developed to study the cavitation characteristics, formation conditions, and development of cavitating flow in viscous oil around a hydrofoil under various flow conditions. Moreover, a visual experimental system in which viscous oil flowed around the hydrofoil was proposed and developed to investigate the cavitation properties with regard to various flow conditions. Both numerical results and experimental data indicated that cavitation occurred on the suction surface of the hydrofoil head, and the cavitation characteristics in viscous oil are significantly influenced by the flow conditions. The maximum vapor volume change rate for the degree of effects on cavitation in viscous oil by flow conditions was calculated to be 1.78 cm3/(m/s), −130.66 cm3/MPa, 0.16 cm3/°C, and 4.52 cm3/°, respectively. Low velocities, high pressures, low temperatures, and small impact angles were proved to be able to suppress cavitation. This study provides a research method, an experimental mean, and data support for cavitation flow of viscous fluids, especially oil. It has significant engineering application significance for the development of fluid machinery.

Effect of Humidity on Head Smear Generation in Head-Assisted Magnetic Recording

The causes of head smears deposited on the magnetic head surface due to laser heating in heat-assisted magnetic recording should be investigated to achieve high recording densities of hard disk drives. These factors, such as outgassing from components and humidity, also affect smear formation in hard disk drives. In this study, we focused on the effect of relative humidity on smears generated via laser heating. Three types of lubricant film (dipped, ultraviolet-treated, and rinsed) were prepared, and the amount of smear generated on a glass pin surface was evaluated using a pin-on-disk tester with a laser heating system. It was confirmed that the amount of smear increased as the humidity increased, and lubricant films with higher chemical bonding fractions showed less smear generation and lower dependence on humidity. In addition, time-of-flight secondary ion mass spectroscopy confirmed that the migration of cobalt from the magnetic layer was accelerated by laser heating and humidity.

Real-time prediction for temperature distribution on the cylinder head of dual-fuel engines via a novel deep learning framework

The mixture of dual fuels causes a complex in-cylinder combustion reaction for dual-fuel engines, which may result in an excessively high thermal load for the cylinder head. Whereafter, the cylinder head is more prone to failures such as thermal fatigue. Considering that temperature distribution on the fire-contact surface of the cylinder head is an important indicator characterizing the thermal load of the cylinder head, with the online pressure sensor data, a real-time prediction methodology based on a novel deep learning framework (UR-CNN) is proposed in this work to predict temperature distribution on the cylinder head. Therein, the feature information contained in the operating parameters of dual-fuel engines is considered by UR-CNN while establishing the relationship between the temperature distribution and pressure sensor data, thereby UR-CNN possesses a better generalization performance for new operating conditions. The results in case studies validate the effectiveness and superiority of UR-CNN in the prediction of temperature distribution on the cylinder head. Hence, the proposed method provides a new approach for the real-time prediction of temperature distribution on the cylinder head in engineering applications, which contributes to the real-time evaluation of whether the thermal load of the cylinder head exceeds the threshold specified by design guidelines.

Damage-Based Assessment of the Risk of Cut-Out in Trochanteric Fractures for Different Proximal Femoral Nail Anti-Rotation (PFNA) Blade Positions

Cut-out of the hip blade of fracture fixation implants, defined as the perforation of the femoral head by the blade due to the collapse of the neck-shaft angle into varus, is the most relevant mechanical complication in the treatment of trochanteric fractures. Among the factors that contribute to cut-out, the blade positioning in the femoral head is reported as one of the most relevant. Since the optimal blade position in the superior–inferior and medial–lateral directions is unknown, the goal of this work was to investigate the impact of blade positioning in these directions, using three-dimensional finite element models of two femora with an unstable trochanteric fracture (31-A2.2 in the Müller AO classification system with an intrusion distance of 95% of the fracture line length). The finite element models developed were coupled with a stiffness-adaptive damage model for the evaluation of the risk of cut-out. The Proximal Femoral Nail Anti-rotation (PFNA) blade was placed in each model at four discrete distances from the femoral head surface in central and inferior positions. The damage distribution in bone resulting from a gait loading condition was visually and quantitatively assessed to compare the performance of the eight positions and predict the relative risk of cut-out for each. The results suggest that the closer the tip of the blade to the femoral head surface, the lower the risk of cut-out. In the superior–inferior direction, contradicting findings were obtained for the modelled femora. The depth of placement of the blade in the medial–lateral direction and its superior–inferior position were shown to have great influence in the risk of cut-out, with the medial–lateral position being the most relevant predictor. The optimal blade positioning may be subject-specific, depending on bone geometry and density distribution.

Low-cost, smartphone-based instant three-dimensional registration system for infant functional near-infrared spectroscopy applications.

To effectively apply functional near-infrared spectroscopy (fNIRS)/diffuse optical tomography (DOT) devices, a three-dimensional (3D) model of the position of each optode on a subject's scalp and the positions of that subject's cranial landmarks are critical. Obtaining this information accurately in infants, who rarely stop moving, is an ongoing challenge. We propose a smartphone-based registration system that can potentially achieve a full-head 3D scan of a 6-month-old infant instantly. The proposed system is remotely controlled by a custom-designed Bluetooth controller. The scanned images can either be manually or automatically aligned to generate a 3D head surface model. A full-head 3D scan of a 6-month-old infant can be achieved within 2s via this system. In testing on a realistic but static infant head model, the average Euclidean error of optode position using this device was 1.8mm. This low-cost 3D registration system therefore has the potential to permit accurate and near-instant fNIRS/DOT spatial registration.