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This study aimed to compare the corrosion cast models of the porcine head arterial system with three-dimensional (3D) reconstructions using cone beam computed tomography (CBCT) of these cast models. Six heads from sows were simultaneously injected through both carotid arteries with Duracryl Plus for corrosion cast technique and an additional head, also from another one sow head, was filled with saturated lead tetroxide (Pb3O4) in a 10% hot water solution (40°C) of gelatin for CBCT study. Two-dimensional (2D) images were stored in Digital Imaging and Communications in Medicine (DICOM). Subsequently, segmentation and post-processing of these images were performed by using various software programs. The 3D models were found to be compatible with the corrosion cast models. It was observed that osseous structures and arteries were clearly identified on CBCT images. Specimen scan, segmentation, and post segmentation had a duration of 10-15 minutes, 4 hours, and 15 minutes, respectively. The internal carotid artery, external carotid artery, and its main branches were seen well on 3D models. In conclusion, it is considered that 3D models and images can be effectively used in anatomy education, radiological evaluations, pathological and variational investigations.

A novel ultrasonic burnishing (UB) system with a flat tool using a piezoelectric longitudinal transducer (PLT) is proposed. High-precision no-feeding mark planar burnishing can be achieved by the compact system with a size of only 280 mm 224 mm 558 mm without the need for machine tools. Above all, the structure of the burnishing system is presented and the operation principle is analyzed in detail. A resonant frequency design method of the PLT with a tool head is discussed. Based on thisthe PLT achieves the expected resonant frequency precisely. Subsequently, the test system for the PLT is built and the resonant frequency and vibration amplitude are tested, which are in good agreement with the simulation results. Ultimately, the UB experiments are carried out and the results indicate that the surface roughness of the workpiece is reduced from Ra 1.6 m to Ra 0.182 m, which is reduced by 88.31%. Furthermore, the surface topography shows that the surface without the feeding mark is generated, which is beneficial to improve the burnishing accuracy and expand the application in ultra-precision processing.

Accurate assessment of total body composition in tall (1.96m) individuals using dual energy x-ray absorptiometry (DXA) scans is problematic due to current height restrictions of the scan table. The aim of this investigation was to quantify absolute and relative contributions of fat, bone and lean mass, of the feet and head regions, to whole-body composition DXA scan totals. Whole-body DXA scans were performed in collegiate athletes. Athlete DXA scans were included in data analyses if the entire body fit within the confines of scan table area. The feet region of interest (ROI) was delineated at the ankle joint mortise, marked superiorly by the inferior margin of the tibial plafond and encompassing all inferior anatomical structures. The head region was calculated by the DXA scan software. Both absolute (kg) and relative (feet/whole-body x 100 = feet mass %) contributions to body composition were calculated. Data presented as mean±SD. 132 National Collegiate Athletic Association (NCAA) athletes (85 female) underwent DXA scans which met the inclusion criteria. The feet region represented: 1.9±0.3kg (2.6±0.3%) of total mass; 0.4±0.3kg (2.6±0.5%) of fat mass; 1.3±0.3kg (2.5±0.3%) of lean mass; and 0.14±0.0kg (5.4±0.6%) of bone mineral content (BMC). The head region represented: 4.8±0.5kg (6.9±0.8%) of total mass; 1.2±0.2kg (8.2±3.0%) of fat mass; 3.2±0.5kg (6.1±0.9%) of lean mass; and 0.48±0.07kg (18.7±2.7%) of BMC. Significant negative relationships were found between head% versus whole-body BMC (r=-0.54;p0.0001), lean mass (r=-0.57;p0.0001), and fat mass (r=-0.81;p0.0001) and between feet% versus fat mass (r=-0.68;p0.0001). A significant positive relationship was noted between feet% versus whole-body BMC (r=0.18;p=0.04) but not versus lean mass (r=0.15;p=0.09). Removing the feet from whole-body composition analyses reduces lean, fat and bone mass compartment totals by 3%-5%. Removing the head region reduces body composition compartments by 6%-19%, from whole-body DXA scan totals.

Throughout evolution, organisms repeatedly developed elastic elements to power explosive body motions, overcoming ubiquitous limits on the power capacity of fast-contracting muscles. Seahorses evolved such a latch-mediated spring-actuated (LaMSA) mechanism; however, it is unclear how this mechanism powers the two complementary functions necessary for feeding: rapidly swinging the head towards the prey, and sucking water into the mouth to entrain it. Here, we combine flow visualization and hydrodynamic modelling to estimate the net power required for accelerating the suction feeding flows in 13 fish species. We show that the mass-specific power of suction feeding in seahorses is approximately three times higher than the maximum recorded from any vertebrate muscle, resulting in suction flows that are approximately eight times faster than similar-sized fishes. Using material testing, we reveal that the rapid contraction of the sternohyoideus tendons can release approximately 72% of the power needed to accelerate the water into the mouth. We conclude that the LaMSA system in seahorses is powered by two elastic elements, the sternohyoideus and epaxial tendons. These elements jointly actuate the coordinated acceleration of the head and the fluid in front of the mouth. These findings extend the known function, capacity and design of LaMSA systems.

Leakage-induced hydraulic and ground responses in a twin-tunnel system are analyzed via the proposed analytical solution on the seepage field. The seepage continuity conditions are rigorously satisfied at the interface between the ground and the tunnel lining, in terms of both water pressure and seepage velocity. The analytical solution is verified by comparing the results of numerical simulations. A detailed parametric analysis is carried out to explore the effect of tunnels’ spatial layouts and degraded waterproof facilities on leakage-induced hydraulic and ground response, including head decline, water inflow and ground surface settlement. Our results show that the often used single tunnel model tends to overestimate the pore pressure on the lining along with water inflow into the tunnel, and underestimate the leakage-induced ground settlement.

Objectives This study evaluated optimum stability of different screw techniques for condylar head fractures (CHF) (P close to an M fracture with the lateral pole preserved according to AO classification 2014) by finite element analysis (FEA) and provided a biomechanical basis for clinical treatment. Study Design Four CHF fixation models were evaluated: (A) single bicortical screw, (B) 2 bicortical screws, (C) 1 bicortical screw and 1 monocortical screw (used as a positional screw) inserted via a 2-hole titanium plate, and (D) 2 bicortical screws inserted via a titanium plate. Stresses were calculated (FEA) to measure mechanical properties. Results The displacement for A and C was larger than for B and D. The maximum stress on the screws for A and C exceeded their breaking limit but was safe for B and D. The stress on the titanium plate for C and D was safe. The stress on bone for A and C was larger than for B and D. Conclusions The 2 bicortical screw fixation reduced the stress on implanted materials and surrounding bone tissue. Titanium plates further alleviated the lever action. Two bicortical screw fixation was more reliable for CHF, and early postoperative loading and functional training can be expected.

Overfall spillways are important hydraulic structures for the release of overtopping water flows downstream of a dam. To reduce the effects of the impact of falling water in plunge pools, an overfall spillway outlet design that produces a longitudinally spreading jet is required. This study examined the effects of a triangular wedge placed at the end of an overfall spillway to deflect the water flow in the lateral direction, making the jet longitudinally diffuse before reaching the plunge pool. Laboratory data on the mean pressure coefficient were used to analyse the effects of various design parameters. An increase in the deflection ratio and a decrease in the weir crest length reduced the jet impact pressure. Compared with the impact of a rectangular jet falling into a plunge pool, an appropriate triangular wedge structure was found to improve the spreading of the impingement jet and reduce the mean dynamic pressure coefficient. By optimising the geometric design to accomplish jet impact control, the results of the present investigation may help engineers to design overfall spillways in high-head dam projects.

In order to satisfy the machining requirements of aero-engine casing in modern aviation industry, this paper investigates three main issues during the design and development process of a five-axis machine tool with high accuracy, stiffness and efficiency, including whole structure design, key components design, and supporting stiffness design. First, an appropriate structure of five-axis machine tool is determined considering the processing characteristics of aero-engine casing. Then, a dual drive swing head and a compact motorized spindle are designed with enough drive capability and stiffness, and related structure, assembly method, cooling technology, and performance simulation are given in detail. Next, a design method of supporting stiffness of guide is proposed through the deformation prediction of the spindle end. Based on above work, a prototype of machine tool is developed, and some experiments are carried out, including performance tests of swing head and motorized spindle, and machining of a simulated workpiece of aero-engine casing. All experimental results show that the machine tool has satisfactory accuracy, stiffness and efficiency, which meets the machining requirements of aero-engine casing. The main work can be used as references for engineers and technicians, which are meaningful in practice.

Objective We conducted a driving simulator study to investigate scanning and hazard detection before entering an intersection. Background Insufficient scanning has been suggested as a factor contributing to intersection crashes. However, little is known about the relative importance of the head and eye movement components of that scanning in peripheral hazard detection. Methods Eleven older (mean 67 years) and 18 younger (mean 27 years) current drivers drove in a simulator while their head and eye movements were tracked. They completed two city drives (42 intersections per drive) with motorcycle hazards appearing at 16 four-way intersections per drive. Results Older subjects missed more hazards (10.2% vs. 5.2%). Failing to make a scan with a substantial head movement was the primary reason for missed hazards. When hazards were detected, older drivers had longer RTs (2.6s vs. 2.3s), but drove more slowly; thus, safe response rates did not differ between the two groups (older 83%; younger 82%). Safe responses were associated with larger (28.8° vs. 20.6°) and more numerous (9.4 vs. 6.6) gaze scans. Scans containing a head movement were stronger predictors of safe responses than scans containing only eye movements. Conclusion Our results highlight the importance of making large scans with a substantial head movement before entering an intersection. Eye-only scans played little role in detection and safe responses to peripheral hazards. Application Driver training programs should address the importance of making large scans with a substantial head movement before entering an intersection.

In this study, a combined experimental, numerical and theoretical investigation is conducted on the penetration of semi-infinite 4340 steel targets by a homogeneous 93W rod and two types of jacketed rods with striking velocities of 0.9-3.3 km/s. The results show that the jacketed rods produced typical “co-erosion” damage at all test velocities, except for the 93W/1060Al jacketed rod, which switched from an early “bi-erosion” damage to later “co-erosion” damage at a striking velocity of 936 m/s. However, the homogeneous 93W rod always forms a large mushroom head during the penetration process. The damage mechanisms of these two types of jacketed rods differ for striking velocities of 0.9–2.0 km/s, but this difference gradually decreases with increased striking velocity. For velocities of 2.0–3.3 km/s, all three types of projectiles exhibit typical hydrodynamic penetration characteristics, and the damage mechanisms of the two types of jacketed rods are almost identical. For the same initial kinetic energy, the penetration performance of the jacketed rods is distinctly superior to that of the homogeneous 93W rods. Compared with jacket density, jacket strength shows a more significant influence on the damage mechanism and penetration performance of the jacketed rod. Finally, an existing theoretical prediction model of the penetration depth of jacketed rods on semi-infinite targets in the co-erosion mode is modified. It transpires that—in terms of penetration depth—the modified theoretical model is in good agreement with the experimental and numerical observations for 93W/TC4 and 93W/1060Al jacketed rods penetrating semi-infinite 4340 steel targets.

Leakage is always a concern in the interface between the cylinder block and the head. Nowadays, sealing of this interface is almost exclusively achieved by multi-layer steel head gaskets. However, it is not only the gasket's quality that is responsible for perfect sealing. An equally important role is played by the surface topography of the mating surfaces. The top surface of the cylinder block and the bottom surface of the cylinder head are machined by face-milling and present periodic tool marks features. Based on the surface topography measured by high definition metrology, this paper presents a novel sealing analysis method to evaluate the sealing performance of the critical topography region around the combustion chambers. The method consists of three modules: tool paths or channels reconstruction, sealing region segmentation based on channels' directions, and sealing analysis on sealing regions with different channel directions. An engineering case demonstrates the sealing analysis procedures and verifies the effectiveness of the sealing analysis method. The analysis of 12 ring-shaped sealing regions found that channels' directions do have a significant impact on surfaces' sealing properties. Circumferential channels or paths are advantageous for surface sealing, while radial channels are prone to leakage.

A numerical calculation model of multihead twisted spiral tube was established. In the range of Reynolds number from 5000 to 35000, the influence of different twisted structure on the flow and heat transfer characteristics of the multihead twisted spiral tube was studied by numerical calculation. Numerical calculation results indicate that the Nusselt number and friction coefficient increase with the increase in the ratio of outside and inside diameter of the cross-section, the increase in the number of twisted nodes, and the increase in the number of twisted spiral tube heads. Under the condition of the same spiral structure and the same hydraulic diameter, the heat transfer performance of the multihead twisted spiral tube is better than that of the spiral smooth tube. In addition, through artificial neural network analysis, the ratio of outside and inside diameter of the cross-section, number of twisted nodes, and the number of twisted spiral tube heads were optimized to promote the comprehensive heat transfer performance. The performance evaluation criterion is the highest when the ratio of outside and in-side diameter of the cross-section is 25/22.5, the number of twisted nodes is 3, and the number of twisted spiral tube heads is 3, which is 1.849 of the spiral smooth tube.

Hump characteristic is one of unique hydraulic instabilities of pump-turbines, which restricts the stable and safe operating range of the units. High-amplitude pressure fluctuations could be observed in the hump region, leading to hydraulic vibration of pumped storage power plants. To reduce the high-amplitude pressure fluctuation in the hump region, two optimization strategies for high-pressure edge shape of runner blades have been proposed. One is to increase the outlet angle near the shroud and the other increases the radius near the shroud. A large eddy simulation, which has been validated using performance and pressure fluctuation experiments, was performed to study the optimization effect. The valley point (0.65QBEP) in the hump region was selected for conducting time and frequency analyses under different optimization strategies. Analyses show that the pressure fluctuations were primarily caused by the rotation of three low-pressure regions at the circumference of the guide vanes. Both optimization strategies reduced the stall vortices formed in the three low-pressure regions and mitigated the rotating stall phenomenon. The influence of the runner-outlet geometries on pressure fluctuations is primarily reflected in the amplitude reduction of the dominant low frequency 0.2fn (where fn denotes the rotational speed) in the vaneless region and guide/stay vanes. Compared with strategies involving larger outlet angles near the shroud, this strategy of increasing the radius can more effectively reduce the amplitude of the dominant low frequency, and it makes the circumferential distribution of pressure fluctuations more uniform. These findings can help guide efforts in pump-turbine design optimization, which have been applied in a 700 m head pump-turbine design.

The formation mechanism of an EFP(explosively formed projectile) using a double curvature liner under the overpressure effect generated by a regular oblique reflection was investigated in this paper. Based on the detonation wave propagation theory, the change of the incident angle of the detonation wave collision at different positions and the distribution area of the overpressure on the surface of the liner were calculated. Three-dimensional numerical simulations of the formation process of the EFP with tail as well as the ability to penetrate 45# steel were performed using LS-DYNA software, and the EFP velocity, the penetration ability, and the forming were assessed via experiments and x-ray photographs. The experimental results coincides with those of the simulations. Results indicate that the collision of the detonation wave was controlled to be a regular oblique reflection acting on the liner by setting the dimensions of the unit charge and maintaining the pressure at the collision point region at more than 2.4 times the CJ detonation when the incident angle approached the critical angle. The distance from the liner midline to the boundary of the area within which the pressure ratio of the regular oblique reflection pressure to the CJ detonation pressure was greater than 2.5, 2, and 1.5was approximately 0.66 mm, 1.32 mm, and 3.3 mm, respectively. It is noted that pressure gradient caused the liner to turn inside out in the middle to form the head of the EFP and close the two tails of the EFP at approximately 120μs. The penetration depth of the EFP into a 45# steel target exceeded 30 mm, and there was radial expansion between the head and tail of the EFP, increasing the penetration resistance of the EFP. Therefore, the structural size of the unit charge and the liner can be further optimized to reduce resistance to increase the penetration ability of the EFP.

A new friction-based riveting technique, Rotating Hammer Riveting (RHR), is demonstrated to fully form AZ31 Mg rivet heads in a mere 0.23 s. Heat and pressure generated through severe plastic deformation during the process was sufficient to form the Mg rivet head without the need for a pre-heating operation. Due to preliminary twinning and followed by dynamic recrystallization, AZ31 Mg grains in the rivet head were refined during RHR, which enhance the formability of Mg rivets by triggering grain boundary sliding and reducing plastic anisotropy of Mg. In addition, RHR joints showed a metallurgical bond between the rivet head and top AZ31 Mg sheet, which eliminates a significant pathway for corrosion.

This paper presents a numerical investigation of two-phase natural circulation flows established when external reactor vessel cooling is applied to a severe accident of the APR1400 reactor for the in-vessel retention of the core melt. The coolability limit due to external reactor vessel cooling is associated with the natural circulation flow rate around the lower head of the reactor vessel. For an elaborate prediction of the natural circulation flow rate using a thermal-hydraulic system code, MARS-KS1.5, a three-dimensional computational fluid dynamics (CFD) simulation is conducted to estimate the flow rate and pressure distribution of a liquid-state coolant at the brink of significant void generation. The CFD calculation results are used to determine the loss coefficient at major flow junctions, where substantial pressure losses are expected, in the nodalization scheme of the MARS-KS code such that the single-phase flow rate is the same as that predicted via CFD simulations. Subsequently, the MARS-KS analysis is performed for the two-phase natural circulation regime, and the transient behavior of the main thermal-hydraulic variables is investigated.

Explosive launching devices are used to test objects of rocket and space technology for resistance to the impact of meteoroids and fragments of space debris. These include shaped charges with a combined hemisphere-cylinder liner. In these charges, the formation of a high-velocity compact element occurs as a result of “cutting-off” by the collapsing liner cylindrical part of the head section of the jet flow formed from the liner hemispherical part compressed by the explosion products. Currently used shaped charges with a hemisphere-cylinder liner make it possible to obtain compact steel elements with velocities of 6 km/s. It was considered the possibility of obtaining aluminum particles with velocities up to 16 km/s using shaped charges with a combined shaped-charge liner on the basis of numerical modeling within the framework of a two-dimensional axisymmetric problem of continuum mechanics. The modeling was carried out for a shaped charge with a diameter of 100 mm using the ANSYS/AUTODYN and ERUDIT computer codes. To achieve this goal, a degressive (decreasing from apex to base) thickness was given to the jet-forming part of the liner, and the surfaces bounding it had the form of surfaces of a semi-ellipsoid or semi-superellipsoid of revolution. The geometric parameters of the combined liner were selected based on the results of the calculations, which made it possible to form an aluminum particle with a considered level of velocity with its mass in tenths of a gram.

Archimedes screw is one of the biggest innovations that the human mankind has ever experienced. From the day of its innovation AST has upgraded the lives of the people. Various studies have been done considering various parameters and the results shows that the maximum efficiency is recorded in between 20 and 25 degrees, but the accurate angle hasn’t been shown in any of the study. The experimentation study reveals that the maximum efficiency of 74.27% is recorded at 22 degrees with flow rate of 1 l/s and load of 0.9 kg. Maximum output power of 0.00577 kW was recorded at load 0.9 kg and Flow rate 4 l/s at 25-degree tilt angle. maximum speed of 141 RPM was recorded at load 0.5 kg at Tilt angle of 25 degree and at 4 l/s of flow rate. The results show the feasibility of AST to be installed at low head sites at low tilt angle and at heavy loads.

Background/Aim. It is possible that patients with open-angle glaucoma be asymptomatic in the early stage of the disease. The aim of this study was to determine the structural and vascular changes of the optic disc (OD) and macula in healthy and primary open-angle glaucoma (POAG) eyes, detected by optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) as well as the correlation of the OCT and OCTA measurements and their association with the presence of POAG. Methods. A total of 196 eyes were included and classified into four groups, out of them 48 were healthy eyes, 51 eyes were with mild POAG, 50 eyes with moderate POAG, and 47 eyes with advanced glaucoma. All subjects underwent standard ophthalmic examination. OCT measured the mean, superior and inferior retinal nerve fiber layer (RNFL) thickness and macular ganglion cell complex (GCC). OCTA evaluated the vessel capillary density (VCD) in OD, foveal avascular zone (FAZ) and macular vessel density (VD) in the superficial (SL) and deep (DL) retinal vascular plexus. Results. Patient characteristics were similar except for decreased visual acuity, thinner corneas, higher intraocular pressure and higher cup/disc ratio in POAG patients. OCT results showed that RNFL and GCC thickness gradually de-creased according to POAG severity. Within the assessment conducted by OCTA, VCD?s value in OD also diminished with the progression of POAG, having the lowest value in patients with advanced glaucoma. The same pattern was observed in vessel density around FAZ and VD values. Comparing the structural and vascular changes, a significant positive correlation was found between RNFL thickness and VCD inside OD, and GCC and VD SL in the macular zone. Conclusion. OCT and OCTA allow of a noninvasive quantification of the structural and vascular changes in OD and the macular zone and accurately distinguish between healthy eyes and eyes with POAG, showing an association with the presence and progression of glaucoma.

Headed bars (HB) with different head shapes (Square, Circular, and Rectangular) and bar diameters (db: 16, 20, and 25 mm) embedded in steel fiber reinforced concrete have been subjected to pull-out test. The influence of head shapes, concrete compressive strength (M20 and M40), db, and steel fibers (0, 0.5, 1, and 1.5%) on the anchorage capacity of HB have been evaluated. Numerical model for improving the anchorage capacity of HB has also been proposed. Results have revealed that the anchorage capacity of HB increases with the increase in concrete compressive strength, db, and steel fibers, which have been validated by nonlinear regression analysis using dummy variables. Two failure modes namely, steel and concrete-blowout have been observed and the prevailing mode of failure is steel failure. Based on load–deflection curves and derived descriptive equations, it is observed that the circular HB has displayed the highest peak load.

Ammonia synthesis is a crucial section of ammonia and urea plant. Many industries are facing a challenge of efficient ammonia production every day. In this study, steady state one dimensional pseudo-homogeneous models of an axial flow industrial catalytic packed bed ammonia converter have been developed. The converter is a vertical two catalytic bed reactor with varying volumes of catalysts. Required industrial data for the design were collected from a real fertilizer industry in Bangladesh (RFIB) and the Halder Topsoe process was followed. Differential equations of the the developed mathematical model was solved using Runge-Kutta-Fehlberg (RKF45) method by Polymath solver software. For a 23.8% single-pass conversion total 22.5 (15 + 7.5) m catalyst bed required. Pressure vessel wall and head thickness were found 112 mm and 62 mm respectively. Skirt support was selected and the thickness was calculated 12 mm. Pressure drop along the length of the bed was calculated and the value was found 2.55 atm. Finally, parameters of the optimized model were compared with the real plant data and quite satisfactory result were obtained.

Constant head tests are commonly used for field measurements of fracture transmissivity. As a bulk transmissivity is measured for each test section, it is frequently unclear how this transmissivity relates to the hydraulic properties of individual fractures. The goal of this study is to determine if constant head tests conducted at scales larger than the average fracture spacing can be used to generate discrete fracture network (DFN) models that describe transport. The methodology involved generating DFNs using measurements from constant head tests conducted at lengths both above and below the average fracture spacing at a site in Ontario, Canada. Transport predictions from DFNs produced from different scales of hydraulic tests were compared to determine if a method for proportioning larger-scale test results to obtain a DFN representative of the smaller-scale tests could be established. The results of this study indicate that the choice of method used to apportion bulk transmissivities has a significant impact on transport simulations, with a difference in mass arrival of over a factor of two at travel distances less than 50 m. While the most appropriate method is case specific, the error resulting from the choice needs to be considered when using DFN models.

The current work deals with the methodological study of pressure vessel (Cylindrical or spherical) with different ends or heads. The pressure vessel is designed for 24 L volume and 8 bar pressure vessels are done following ASME standard section VIII, Division I. The thickness of all cylindrical heads is calculated by different formulae and the thickness vary accordingly. However, in this project, the thickness is kept constant irrespective of cylindrical heads or ends to study its effect. FEA is performed to evaluate or study the stress parameters. The software took for Finite Element Analysis (FEA) in Ansys 19.2. Before that, the 3D modelling was done using SolidWorks software. After concluding the better cylindrical end or head for constant thickness, the comparison of the material is made to compare with the current state of the art and find out the better material by analyzing the circumferential stress and longitudinal stress.

Purpose: We aimed to investigate the benefit of a screening tool in selecting head-injured children who can potentially cooperate with computed tomography (CT).Methods: The study population consisted of head-injured children aged 36 months or younger who visited the emergency department (ED) and underwent CT from January 2013 through December 2020. Procedural sedation and analgesia (PSA) using per os chloral hydrate or per rectal thiopental was implemented to children presumed less cooperative for CT as per a clinical screening tool for cooperative candidates for CT (e.g., ability to lie still on bed for 10 seconds without a guardian). According to the PSA and the first attempt success of CT, we compared baseline characteristics, CT findings, clinically important traumatic brain injury, ED length of stay (EDLOS), and ED disposition.Results: Among the 247 children, PSA was used in 102 (41.3%). The PSA group showed a higher proportion of 3-36 months of age (PSA, 96.1% vs. non-PSA, 82.8%; P = 0.001) and longer median EDLOS (PSA, 127.0 [interquartile range, 101.0-172.0] vs. non-PSA, 85.0 minutes [63.0-130.0]; P < 0.001). The number of children undergoing the first attempt success was 213 (86.2%) without a difference in both groups (PSA, 84.3% vs. non-PSA, 87.6%; P = 0.645). In the 213 children, the implementation of PSA was associated with longer median EDLOS (PSA, 121.0 [99.0-156.0] vs. non-PSA, 77.0 minutes [60.0-122.0]; P < 0.001). In the non-PSA group (n = 145), the first attempt failure was associated with the presence of skull fracture (success, 7.1% vs. failure, 27.8%; P = 0.009).Conclusion: This study suggests a potential benefit of the screening tool in selecting cooperative candidates for CT, i.e., those who could forgo PSA using oral chloral hydrate or per rectal thiopental, in young children with head injury.

A new type series inertance tube pulse tube refrigerator is introduced. It includes series cold heads. Each cold head's pulse tube connects an inertance tube as phase shifter. The acoustic power of the first pulse tube is partially used by the first inertance tube for phase shifting, while the remaining is used for generating additional cooling power. It is high efficiency with multi refrigeration temperature. A two-dimensional axisymmetric model was introduced for simulation by the commercial CFD software ANSYS Fluent. The numerical results show that it has high potential for getting higher efficiency. A protype series inertance tube pulse tube refrigerator was made and tested. Its efficiency is higher than the ordinary inertance tube pulse tube refrigerator at higher temperature range. At 232K, the efficiency is increased by 10%. The results show that it is valuable for further development.

Phantoms are critical items for testing and evaluating new prototypes of electromagnetic medical imaging systems. Realistic tissues distribution, size, shape, and dielectric properties of tissue-mimicking materials across the desired frequency band; in addition, long-term stability is required. In this study, a polymer composition that use to develop head tissues-mimicking materials that satisfy the aforementioned requirements. Polyepoxides (Epoxy), and assorted types of micro scale additive, including graphite, aluminium oxide, carbon black, and brass powders, are used to fabricate the phantom. Different mixing ratios are used to mimic four healthy head tissues; white matter, grey matter, skull, and skin. Blood-mimicking material is also included in the unhealthy phantom to represent stroke (hemorrhagic) at different locations and sizes. Also, water-based mimicking material is used to emulate cerebrospinal fluid (CSF) tissue. The measurements confirm close agreement to properties of actual head tissues across the frequency band 0.5–5 GHz, which has been used in the ongoing research activities of electromagnetic head imaging systems. Stability over time is investigated and compared with the widely used gelatin-in water-based mimicking materials. The results show the superiority of the developed phantom compared to currently using gelatin-based phantoms.

Objective : The purpose of this work was to enable simultaneous head and spine Magnetic Resonance imaging (MRI) in children at 3T by using a dedicated multichannel radiofrequency coil array system. Methods : A 24-channel head and spine pediatric coil system was developed and constructed. The coil's performance was compared with a commercially available 24-channel adult head-neck coil and a spine coil (1-4 spine of 16-channel were selected). Signal-to-noise ratio (SNR) and parallel imaging capability were quantitatively evaluated by phantom studies and in vivo imaging experiments. With Institutional Review Board and Ethics Committee approval, the designed coil was used to acquire head and spine images on 27 children in clinical settings. Results : The pediatric coil provided substantial SNR improvements with an increase of 32% to 40% in the brain region and up to a two-fold increase in the surface. SNR increased by at least 18% in the spine region. The coil enabled higher resolution and a faster imaging speed, owing to significantly improved SNR. Extensive coverage of the coil enabled high-quality fast imaging from head-neck to the whole spine. Good image quality with an average score 4.63 out of 5 was achieved using the developed pediatric coil in clinical studies. Conclusion : Simultaneous head and spine MRI with superior performance have been successfully acquired in children subjects at 3T using the dedicated 24-channel head and spine pediatric coil system. Significance : The 24-channel pediatric coil system potentially can enhance pediatric head and spine MRI in clinical research and diagnosis.

Sex, head and neck posture, and cervical muscle preparation are contributing factors in the severity of head and neck injuries. However, it is unknown how these factors modulate the head kinematics. In this study, twenty-four (16 male and 8 female) participants experienced 50 impulsive forces to their heads with and without an acoustic warning. Female participants demonstrated a 71 ms faster (p = 0.002) muscle activation onset compared to males after warning. The magnitude of muscle activation was not significant between sexes. Females exhibited 21% (p < 0.008) greater peak angular velocity in all force directions and 18% (p < 0.04) greater peak angular acceleration in sagittal plane compared to males. Females exhibited 15% (p = 0.03) greater peak linear acceleration compared to males only in sagittal flexion. Preparation attenuated head kinematics significantly (p < 0.03) in 11 out of 18 investigated head kinematics for both sexes. A warning eliciting a startle response 420 ms prior to the impact resulted in significant attenuation of all measured head kinematics in sagittal extension (p < 0.037). In conclusion, both sex and warning type were significant factors in head kinematics. These data provide insight into the complex relationship of muscle activation and sex, and may help identify innovative strategies to reduce head and neck injury risk in sports.

In this work, a numerical calculation was carried out in one of the universal programs for automatic electro-dynamic design. The calculation is aimed at obtaining numerical values for specific absorbed power (SAR). It is the SAR value that can be used to determine the effect of the antenna of a wireless device on biological objects; the dipole parameters will be selected for GSM1800. Investigation of the influence of distance to a cell phone on radiation shows that absorbed in the head of a person the effect of electromagnetic radiation on the brain decreases by three times this is a very important result the SAR value has decreased by almost three times it is acceptable results.

The X-rays were examined, which consist of the effect of 6 MeV energized electrons on different thickness and material of targets, using the MC method. When the PDDs are examined, we can see that the curves obtained for the Target 4 and Target 8 containing only tungsten material are very close PDD values to each other. The highest TPR20,10 value was also obtained for Target 8. For Target 4 and Target 8, which are composed only of tungsten material, when we examine the mean photon energy distributions formed, we observe an increase in energy towards the edge of the field. We obtained the closest TPR20,10 value for Target 6 to the TPR20,10 value generated by the original LINAC target (Target 1). However, the mean photon energy distribution value obtained for Target 6 is higher than the mean photon energy distribution value obtained from the Target 1. The mean photon energy distribution generated by the selected material according to the desired X-ray penetration and the homogeneity of this energy should be considered. The results obtained in the study are of a guiding nature both in modeling studies and for companies that will make target production.

A new species of Phlaeothripinae, Psephenothrips aporosae sp. n., is described based on specimens collected in leaf galls on Aporosa octandra [Phyllanthaceae] in China. The new species is characterized by the head being much shorter than wide, the tube slightly longer than the head, and the metanotum with close longitudinal reticulation.

The article presents the experience of treating wounded K., 29 years old, who, as a result of the suicide bombing of a homemade shell-free explosive device in a moving car of the St. Petersburg Metro 03.04.2017 received a severe mine-explosive combined wound to the head, chest and limbs with a fragmented blind skull. The trauma was accompanied by brain damage, a fracture of the cranial vault bones, lungs contusion, and fragmented fracture of the right tibia bones. The patient underwent sequential bifrontal decompressive craniotomy, external fixation of the right shin bones fractures, blocked intramedullary osteosynthesis of the latter, dura mater plasty, cranioplasty with a titanium plate after its computer modeling. The complex treatment allowed the patient to be discharged from the hospital after 4 months in a satisfactory condition.

Parçacık tedavisinde (PT) genellikle protonlar ve karbon iyonları kullanılır. Fakat protona göre bağıl biyolojik etkileri daha yüksek olan düşük Z’li iyonların (He, O, Ne gibi) kullanımı da araştırılmaktadır. PT’de dozun büyük kısmı, birincil parçacık tarafından tümör hacmine verilmesine rağmen, terapötik ışın ile hastanın dokuları arasındaki etkileşim tarafından üretilen ikincil parçacıkların katkısı nedeniyle ihmal edilemeyecek miktarda ek doz bırakılır. Özellikle nötronlar, tedavi edilen alandan çok uzağa enerji aktararak ikincil kanser riskini artırabilmektedir. Radyasyon tedavisinde yüklü parçacıkları kullanmak için insan dokusuyla birincil parçacık etkileşimleri sonucunda üretilen ikincil nötronları karakterize etmek çok önemlidir. Üretilen ikincil nötronlar detektör veya Monte Carlo (MC) benzetimi gibi yöntemlerle belirlenebilmektedir. Çalışmamızda 50-100 MeV/u enerjili proton ve He iyon ışınları tarafından baş plaka fantomunda üretilen toplam nötron sayıları, nötronlar ve tüm parçacıklar tarafından depolanan dozlar Particle and Heavy Ion Transport Code System (PHITS) MC kodu ile hesaplanmıştır. He iyon demeti tarafından üretilen ikincil nötron sayısı, proton demetlerine kıyasla 7-14 kat arttı. Protonlar tarafından üretilen ikincil nötron dozlarının He iyon demetlerindeki dozların %11.5 - %16.4’ü arasında olduğu hesaplandı., Particle therapy (PT) usually uses protons and carbon ions. In addition, the use of low-Z ions (such as He, O, Ne) with higher relative biological effects than protons is also being investigated. Although in PT the majority of the dose is delivered to the tumor volume by the primary particle, a negligible additional dose is left due to the contribution of secondary particles produced by the interaction between the therapeutic beam and the patient's tissues. In particular, neutrons can increase the risk of secondary cancer by transferring energy far away from the treated area. To use charged particles in radiation therapy, it is crucial to characterize secondary neutrons produced (SNP) as a result of primary particle interactions with human tissue. The SNP can be detected with the detector or by methods such as Monte Carlo (MC) simulation. In our study, the total number of neutrons produced in the slab head phantom by proton and He ion beams with an energy of 50-100 MeV/u, the doses stored by neutrons and all other particles were calculated with the Particle and Heavy Ion Transport Code System (PHITS) MC code. The number of SNP by He ion beam increased 7-14 times compared to proton beams. It was calculated that the doses of the SNP by protons were between 11.5% - 16.4% of those in the He ion beams.

Introduction. The regional vascular centers (RVC) network was created throughout Russia to manage cardiovascular diseases. On the basis of N.V. Sklifosovsky Research Institute for Emergency Medicine in Moscow, a center was created, which received the status of the head RVC. A comprehensive analysis of its work has not yet been carried out.Aim of study. To assess the main performance indicators and development directions of the head RVC based on the analysis of data for 2012–2019.Results. Analysis of the data obtained showed that by 2019 the flow of patient admissions increased 2.3-fold. At the same time, the use of the hospital bed fund does not exceed 100%, and the use of the intensive care bed fund has increased to 123%. A significant proportion of patients come with not field-specific diagnosis. The mortality, which is the main indicator of the quality of treatment in patients treated at the RVC, remained within 2.33–3%, which turned out to be 3 times lower in similar patients treated in other departments of the Institute.Discussion. Against the background of a constant increase in the number of hospitalizations, resusci-tation provision turned out to be insufficient when the number of hospital beds corre-sponded to the flow of admissions. The general lack of intensive care beds in the center and the lack of specialized intensive care for the department of vascular surgery forces the use of other intensive care units of the Institute. The admission of patients with other (not specific for RVC) diagnosis to the vascular center reduces the volume of highly specialized care for specialized patients.Conclusion. The analysis of the performance indicators of the head regional vascular center on the basis of N.V. Sklifosovsky Research Institute for Emergency Medicine, identified the need to expand the resuscitation bed fund in the existing departments of the center and organize specialized resuscitation for patients of the vascular surgery department. Also, the lack of intensive care beds is aggravated by a large flow of non-core admissions. Their reduction with the existing structure will provide significant savings in resources and will increase the number of treated profile patients and improve the quality of highly specialized care.

Purpose The purpose of this paper is to systematically study the dynamic contact stress, frictional heat and temperature field of femoral head-on-acetabular cup contact pairs in a gait cycle. Design/methodology/approach In this paper, four common femoral head-on-acetabular cup contact pairs are used as the research objects, mathematical calculations and finite element simulations are adopted. The contact model of hip joint head and acetabular cup was established by finite element simulation to analyze the stress and temperature distribution of the contact interface. Findings The results show that the contact stress of the head-on-cup interface is inversely proportional to the contact area; high contact stress directly leads to greater frictional heat. However, hip joints with metal-on-polyethylene or ceramic-on-polyethylene paired interfaces have lower frictional heat and show a significant temperature rise in one gait cycle, which may be related to the material properties of the acetabular cup. Originality/value Previous studies about calculating the interface frictional heat always ignore the dynamic change process in the contact load and the contact area. This study considered the dynamic changes of the contact stress and area of the femoral head-on-acetabular cup interface, and four common contact pairs were systematically analyzed.