Mushroom Head Research Articles

Research on sedimentation characteristics of the end bend water extraction project of cascade reservoir backwater

Abstract The operation mode of upstream and downstream cascade power stations significantly impacts the river bed in the water intake section, leading to complex sediment deposition characteristics in the curved river section at the reservoir’s end. In this research, a standard physical model for bed load and suspended load at a scale of λl=λh=100 was conducted, combined with the operation mode of upstream and downstream power stations, to investigate the sediment deposition patterns in the intake section and to study the sediment deposition characteristics in the intake area. The experimental results reveal that bed load sediment predominantly accumulates on the right bank (convex bank) of the river, with no bed load sediment accumulation at the mushroom head layout of the water intake project on the left bank (concave bank). When the operation of upstream and downstream power stations is uncoordinated, suspended sediment settles in the water intake section, with no sediment accumulation in the local area of the mushroom head of the intake due to the disturbance effect. Safety sensitivity analysis indicates that the safety of the water intake project can be ensured.

Research on penetration characteristics of Nb1Zr2Ti1W2 high entropy alloy

The present study reports a novel Nb1Zr2Ti1W2 high entropy alloy (HEA) exhibiting exceptional strength and energy release properties, thereby demonstrating its promising potential for utilization in extreme conditions such as penetration. The penetration of Nb1Zr2Ti1W2 HEA fragments into a semi-infinite high carbon steel target was investigated through an experiment utilizing a 14.5 mm ballistic gun, covering a wide range of impact velocities from 800 to 1600 m/s. The experimental data, encompassing DOP (the depth of penetration) and VOP (the volume of penetration) of HEA fragments at various impact velocities, were acquired. After conducting both macroscopic and microscopic analyses of the crater and residual fragments, we have determined that the penetration pattern of HEA fragments undergoes a transition from a "self-sharpening" to a "mushroom head" across a wide range of impact velocities. The findings indicate that the impact velocity, as well as the biphase structure of Nb1Zr2Ti1W2 HEA (BCC1 and BCC2), are crucial external and internal factors influencing the penetration process. The present study unveils this intriguing physicochemical phenomenon and investigates the correlation between microscopic structure and macroscopic penetration behavior.

Distinct roles of Bdnf I and Bdnf IV transcript variant expression in hippocampal neurons.

Brain-derived neurotrophic factor (Bdnf) plays a critical role in brain development, dendritic growth, synaptic plasticity, as well as learning and memory. The rodent Bdnf gene contains nine 5' non-coding exons (I-IXa), which are spliced to a common 3' coding exon (IX). Transcription of individual Bdnf variants, which all encode the same BDNF protein, is initiated at unique promoters upstream of each non-coding exon, enabling precise spatiotemporal and activity-dependent regulation of Bdnf expression. Although prior evidence suggests that Bdnf transcripts containing exon I (Bdnf I) or exon IV (Bdnf IV) are uniquely regulated by neuronal activity, the functional significance of different Bdnf transcript variants remains unclear. To investigate functional roles of activity-dependent Bdnf I and IV transcripts, we used a CRISPR activation system in which catalytically dead Cas9 fused to a transcriptional activator (VPR) is targeted to individual Bdnf promoters with single guide RNAs, resulting in transcript-specific Bdnf upregulation. Bdnf I upregulation is associated with gene expression changes linked to dendritic growth, while Bdnf IV upregulation is associated with genes that regulate protein catabolism. Upregulation of Bdnf I, but not Bdnf IV, increased mushroom spine density, volume, length, and head diameter, and also produced more complex dendritic arbors in cultured rat hippocampal neurons. In contrast, upregulation of Bdnf IV, but not Bdnf I, in the rat hippocampus attenuated contextual fear expression. Our data suggest that while Bdnf I and IV are both activity-dependent, BDNF produced from these promoters may serve unique cellular, synaptic, and behavioral functions.

Rational construction of mushroom-like Ni@N-doped carbon tubes composites with enhanced electromagnetic wave absorption

It is confirmed that electromagnetic wave absorption (EMA) materials with a metal-carbon dual-phase structure has exposed great potential for achieving tunable, strong, and wide EMA. Herein, the mushroom-like Ni@N-doped carbon tubes (NNCTs) are prepared by nickel-catalyzed growth of carbon tubes, realizing carbon encapsulated metal particles. One end of the carbon tube grows and connects to form a bundle of mushroom-like structures, and the other end of the carbon tube is filled with nickel as the mushroom head. The structure control of NNCTs can be achieved by adjusting the amount of catalyst Ni. Appropriate amount of nickel can control the formation of mushroom-like structure. The results show that the structure has a great influence on the EMA performance. Particularly, NNCT-0.5 provides a minimum reflection loss of -60.47 dB with a thickness of 4.0 mm, and the widest effective absorption bandwidth for RL< -10 dB of NNCT-1.5 at a thickness of 2.00 mm was 7.53 GHz (10.47–18.00 GHz). The immobilization of carbon in melamine was achieved by catalytic generation of carbon tubes with metal ions Ni. Metal-carbon biphasic composites introduce dielectric and magnetic losses. The presence of multiple interfaces and voids in the mushroom structure allows tuning the dielectric parameters and optimizing the impedance matching. This work provides an effective strategy for the fabrication of dielectric and magnetic composites with special structures, which has great potential in attenuating electromagnetic wave energy.

Harvest

Harvest Kieron Walquist (bio) [ See PDF for formatting of the poem. ] I. Chanterelle You cut the mushroom head + leave it overnight face down then a chanterelle spore print on tinfoil— a soft firework a white fern— you show me how to scrape the murmur with a pocketknife to score the little life into a mason jar inoculated ryegrass you can be patient easy with me II. Oyster It shone florescentin the bathroom along the carpet + bathtub border— we washed the outside off only for the mushroom to jungle in when you yanked the inch-high stem as if it were a teenager's boombox cord I unzipped part of me thanked you your willingness [End Page 45] + the other part had lost a comfort— to imagine the oyster an umbrella keeping an unseeable being dry after my shower III. Trumpet Once after sex we laughed about being fruiting bodiesyour breath a warm whistle across the bottle-mouth of my collarbone you said we should flush throughout this season before we were found + picked clean but that night we were boundless you were my comb tooth + I was your trumpet IV. Honey Fungus Their mycelium reaches for milessleeps across state lines you tell me while we hunt in early Junefor coral that if I'm lost among the trees don't look for the sun but the fungi Press your ear to the ground Listen for its pulse Let the orchard orient you I ask [End Page 46] if I were lost where would you be V. Golden Teacher A generous pinch of psilocybin brought me to worship I was a dancer in wool socks the world met me in that melting the bite + beauty of a tongue kiss to a battery something like that how I adored every layer of clothing you took off of me until I realized your hands were my hands slowly defeathering myself VI. Shiitake From an oak older than I'll ever be to the kitchen stove stir-fry shiitakes take on taste you tell me a shadow of other ingredients but it's only texture tough works the jaw like jerky smells of a sore one looks at after ripping [End Page 47] off a band-aid when you turn away I spit VII. Poison Cups A bouquet of night tossed down the log no longer a dead elm but a flute again + again I asked you why were they poisonous no reason you said some are just born bad VIII. Morels In an issue of Missouri Conservationist a nine or ten-year-old me is posing shirtless a dried-apricot-complexion my nipples two dirty pennies I'm wearing morels as fingernails my mouth giving its best grrrthere I'm severe or sassy or stoked or scared I can't tell anymore the title reads Monster Morels the title reads Monster it's your favorite picture [End Page 48] Kieron Walquist Kieron Walquist is a queer, neurodivergent writer and MFA candidate at Washington University in St. Louis. His work appears, or is forthcoming, in Bennington Review, GASHER, Gulf Coast, The Missouri Review, Puerto del Sol, Small Orange, and elsewhere. He lives in Missouri. Copyright © 2022-2023 Pleiades and Pleiades Press

Dynamics of a Laser-Induced Bubble above the Flat Top of a Solid Cylinder—Mushroom-Shaped Bubbles and the Fast Jet

The dynamics of a laser-induced bubble on top of a solid cylinder is studied both experimentally and numerically. When the bubble is generated close to the flat top along the axis of the cylinder and its maximum radius exceeds the one of the flat top surface, it collapses in the form of a mushroom with a footing on the cylinder, a long stem and a hat-like cap typical for a mushroom head. The head may collapse forming a thin, fast liquid jet into the stem, depending on bubble size and bubble distance to the top of the cylinder. Several experimental and numerical examples are given. The results represent a contribution to understand the behavior of bubbles collapsing close to structured surfaces and in particular, how thin, fast jets are generated.

Investigation on the penetration of jacketed rods with striking velocities of 0.9–3.3 km/s into semi-infinite targets

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.

Semi-Crystalline Polymers Applied to Taylor Impact Test: Constitutive, Experimental and FEM Analysis.

Based on mechanical properties of Polyamide 66 (PA66) under complex loading conditions, a Drucker–Prager yield criterion was employed to characterize its yield behavior. Then, a one-dimensional model, which contains a viscoelastic regime and a viscoplastic regime, was introduced and converted into a three-dimensional constitutive model. The three-dimensional model was implemented into a LS-DYNA software, which was used to predict the dynamic response of PA66 under Taylor impact conditions, whose corresponding tests were conducted by gas gun and recorded by high-speed camera. By contrasting the simulation results and these of the corresponding tests, the deformed shapes including the residual length, the maximum diameter and the shape of the mushroom head of the PA66 bars were found to be similar to these obtained from the tests, which verified the accuracy of the three-dimensional constitutive model, and proved that the model was able to be applied to high-rate impact loading conditions.

Study on the optimisation of the end fittings of the DC disconnector

The disconnector is the key electrical equipment in DC field. In China, the ±1100 kV DC project uses the indoor DC field, where the switching impulse withstand voltage of the disconnector influences the clearance a lot. To improve the switching impulse withstand level of the ±1100 kV disconnector, first of all, the switching impulse test was carried out on the disconnector with traditional double-balanced ring structure and the 50% switching impulse discharge voltage was obtained. By analysing the discharge path, it is found that the grading ring did not effectively shield the upper part of the disconnector. Therefore, the structure of the end fittings of the disconnector was changed to the structure of the mushroom head. The electric field simulation was performed on the optimised shield，it is shown that the maximum field strength is lower than the control field strength. Then the switching impulse test was carried out on the optimised disconnector, it was found that the 50% impact discharge voltage was above 2400 kV which met the engineering requirements.

The high performance mushroom-like Pd@SnO2/Ni foam electrode for H2O2 reduction in alkaline media

A novel mushroom-like electrode (Pd@SnO2/Ni foam) is designed and prepared through two step method including of a simple hydrothermal process and an electrodeposition technology. Rutile SnO2 nanorod arrays grow vertically on the Ni foam surface with diameters of around 40 nm, lengths up to around 300 nm and Pd nanoparticles decorate on the top of SnO2 nanorods to form a mushroom-like electrode structure with SnO2 as stem and Pd nanoparticles as mushroom head. The Pd@SnO2/Ni foam electrode exhibits superior catalytic activity and excellent stability at the higher concentration of hydrogen peroxide(H2O2). The reduction current density achieves successfully 320 mA cm−2 at −0.54 V, and it changes barely during 800 potential cycles in 0.5 mol L−1 H2O2 + 3.0 mol L−1 NaOH. The improved performance suggests its promising application as an efficient electrode for H2O2-based fuel cells.

Flexible and Robust Superomniphobic Surfaces Created by Localized Photofluidization of Azopolymer Pillars.

Springtails, insects which breathe through their skins, possess mushroom-shaped nanostructures. As doubly re-entrant geometry in the mushroom head enhances the resistance against liquid invasion, the springtails have robust, liquid-free omniphobic skins. Although omniphobic surfaces are promising for various applications, it remains an important challenge to mimic the structural feature of springtails. This paper presents a pragmatic method to create doubly re-entrant nanostructures and robust superomniphobic surfaces by exploiting localized photofluidization of azopolymers. Irradiation of circularly polarized light reconfigures azopolymer micropillars to have a mushroom-like head with a doubly re-entrant nanogeometry through protrusion and inward bending of polymer film from the top edge. The light-driven reconfigured micropillars facilitate the pining of triple line as the springtails do. In particular, the unique geometry exhibits superomniphobicity even for liquids whose equilibrium contact angles are almost zero in the presence of a practical level of external pressure. In addition, the simple fabrication process is highly reproducible, scalable, and compatible with various substrate materials including flexible polymeric film. Our results suggest that our photofluidization technology will provide a practical route to develop robust superomniphobic surfaces.

Hydraulic experiment on mushroom head in bottom-blown smelting furnace

There are many bottom-blown smelting furnaces in metallurgical industry. When oxygen or air sprays from the jet nozzle into the bottom of the furnace, the melting phase will be frozen and a hemispherical porous zone with a mushroom head shape will be formed around the nozzle. The mushroom head can protect the jet nozzle and mitigate the liquid spray on the surface of melt. In order to analyze the formation process of a mushroom head in the bottom-blown smelting furnaces, a hydraulic experiment system was designed and the formation of the mushroom head was investigated by hydraulic experiment. The hydraulic experiment results show that the formation process is mainly divided into generating crushing generating process and stable mushroom head generation process. The formation of stable mushroom head requires certain thermodynamic condition and water splash is more intense without a mushroom head than with a mushroom head. The size, porosity and diameter of the mushroom head are affected by the flow rate, temperature and heat capacity of the bottom-blowing gas and the temperature of the superheat and the physical parameters of the melt.

LES investigations on effects of the residual bubble on the single hole diesel injector jet

Bubbles surviving from the last injection process play an important role in the early stage of the next injection process, and ultimately affect the quality of diesel spray characteristics. In this paper, a combination of the LES (Large Eddy Simulation) method and VOF (Volume of Fluid) model was applied to study the unsteady liquid jet flow at the early stage of injection coupling the cavitating flow inside orifices, especially to analyze the effects of the residual bubble on the diesel jet. It was found that the instability of the jet surface was intensified by the cavitating flow inside the nozzle. The development of jet instability waves and the cavitation collapse inside the jet aggravated the interactions between air and diesel jet, which caused the liquid core to separate into some large liquid bulks a bit earlier. Then, the ligaments formed from the bulks broke up into droplets. Furthermore, the double mushroom-like shape occurred with the residual bubble, while just a single mushroom head occurred without the residual bubble. The length of liquid core decreased with the increasing of injection pressure, and the phenomenon that the air inside the spray chamber was partly sucked into orifice was observed.

A probable case of Legg-Calvé-Perthes disease in Warring States-era China

Reports of Legg-Calvé-Perthes disease (LCPD) in the paleopathological literature are rare. Here, the authors present a probable case of LCPD, which presents as abnormal morphology of the proximal femur. The condition was observed in an individual of the Warring States period in Shaanxi Province, China, and the morphology involves a “mushroom head” deformity of the proximal right femur and an enlarged acetabulum, along with a contralateral tibia, talus, and navicular that are enlarged and demonstrate periosteal new bone formation. The authors consider tuberculosis, septic arthritis, trauma, slipped capital femoral epiphysis, and Legg-Calvé-Perthes disease in a differential diagnosis. The authors conclude that the most likely diagnosis for the deformity is Legg-Calvé-Perthes disease. Bony changes in the hip joint and contralateral lower leg suggest that the individual had an altered gait because of the condition.

Simulation Research on the Penetration Phenomenon of Long Rod Armour-Piercing Projectile with Different Materials

Using the LS-DYNA software, this paper studied the penetration phenomenon that the long rod armour-piercing projectile with the material of Wf/Zr metallic glass composites and tungsten-alloy penetrating into target. It found that the 93W alloy projectile has a clear mushroom head, and the Wf/Zr metallic glass composite projectile has an acute head and appears “self-sharping” effect obviously. It studied the variation law of the penetration results parameters of the two materials at different penetration initial velocity, and found that the “self-sharping” effect of the Wf/Zr metallic glass composite projectile change to more obvious with the increasing of penetration velocity. It also obtained the change law of the projectile head shape with the penetration velocity.

Outcomes in Advanced Legg-Calvé-Perthes Disease Treated With the Staheli Procedure

Containment and preservation of hip range of motion have been the principles governing the treatment of Legg-Calvé-Perthes disease. The Staheli's slotted acetabular augmentation (SAA) procedure is an alternative approach for older children with Perthes disease with lateral subluxation, incongruent hip, and abduction hinge. It provides effective coverage, restricts lateral displacement of the femoral head, and achieves containment and congruency in short-term follow-up. This study evaluated pre- and postoperative symptoms, range of motion (ROM), and radiographic images in advanced Perthes disease with an incongruent hip or hinge abduction in lateral pillar groups B and C of 21 children who underwent a SAA procedure. Postoperative evaluation showed improved abduction, internal rotation, subluxation ratio, femoral head ratio, and acetabular coverage. At final follow-up, ROM of abduction went from 20° preoperatively to 45° postoperatively, and internal rotation went from 15° preoperatively to 35° postoperatively. The radiographic findings revealed 33% and 38% of patients achieved spherical congruence of the hip and an ovoid or mushroom femoral head, respectively. SAA restricts lateral displacement or subluxation of the femoral head and preserves sphericity, resulting in containment and acetabular coverage.

Self-sharpening phenomena of tungsten fiber composite material penetrators during penetration

Two kinds of the penetrating rods, which were made of tungsten heavy alloy and tungsten-fiber-reinforced Zr-based metallic glass composite material, respectively, were used to penetrate the 30CrMnMo steel target plates in the penetration experiments. In the penetration process, the tungsten heavy alloy rod head formed as a mushroom head and the grains in the head were radially compressed. But in the head of the tungsten-fiber-reinforced Zr-based metallic glass composite rod, the failure along the adiabatic shear bands was observed, which indicated that the tungsten-fiber-reinforced penetrators took on self-sharpening behaviors. A thin edge layer was developed in the tungsten-fiber-reinforced penetrator head and only in this layer the metallic base was broken, the tungsten fibers were ruptured, the temperature increased and the mass was wasted. Evidently, the penetration ability of the tungsten-fiber-reinforced composite material penetrator is evidently greater than that of the tungsten alloy one.

Bubble jet flow formation during boiling of subcooled water on fine wires

Both visual technology and numerical simulation were employed to investigate bubble jet flow formation during boiling of subcooled water on ultrathin platinum wires. Experimental observations and measurements indicated that bubble jet flow formation could be typically divided into three stages: waiting, burst and stably developing stage. A transient numerical model was proposed to simulate the formation process accounting for the thermocapillary force existing at the bubble interface. The dynamical temperature variation in the liquid region, including the regions of the mushroom head and root stem, were numerically analyzed, showing a very good agreement with the experimental observations. The simulation very well explored the physical nature of the dynamical evolution of bubble jet flows and explained the experimental phenomena.

Mosaicplasty with photooxidized, mushroom shaped, bovine, osteochondral xenografts in experimental sheep

The goal was to study the performance of mushroom shaped, photooxidized, osteochondral grafts in mosaicplasty focusing on graft stability and survival. Mushroom shaped, photooxidized grafts (6 mm for the cartilaginous head of the mushroom, 3 mm for the stem) were implanted in the medial femoral condyle of 10 sheep. Four transplants were inserted per condyle in an overlapping fashion using the pressfit technique (n=40 grafts in 10 condyles). The grafts were followed for 6 and 12 months. Semi-quantitative evaluation of graft performance was performed using a validated score system. All grafts were mechanically stable at 6 and 12 months with one exception, where the mushroom head broke off. The formation of cystic lesions in the subchondral bone area was minimal. Repopulation of the old photooxidized cartilage was noticed with cells invading the matrix from the subchondral bone area and also from the pannus on the surface. Fusion between host and graft cartilage was observed in some of the grafts at 12 months, while remodeling of the calcified cartilage zone and tidemark was noticed in all grafts. Results scored significantly better for the 6 months compared to the 12 months group if cartilage surface integrity was compared (p<0.05). In all other variables no significant differences were found between groups. Despite moderate graft recession in the 12 months group partial fusion of grafts and functional results were satisfactory. The photooxidized mushroom shaped osteochondral transplants may be a suitable type of graft for functional results in cartilage resurfacing if stable anchorage of the grafts can be achieved.

Contributions of C. A. P. Turner to Development of Reinforced Concrete Flat Slabs 1905–1909

There is considerable uncertainty regarding both the timing and contributions of various individuals to the development of reinforced concrete flat slabs in the United States. The work of George M. Hill and the patent of Orlando W. Norcross are discussed first to provide context. The significant achievements of Claude A. P. Turner from 1905 to the end of 1909 are then described. Turner’s conceptual design of flat slabs is discussed. Turner conceived a cage of reinforcement, which he called the “mushroom head,” as shear reinforcement. Turner’s simple design for moment led to very small areas of steel flexural reinforcement, which drew criticism from structural engineers. Some early flat-slab buildings and bridges and the load tests that Turner performed are discussed. A tangible symbol of Turner’s contributions is his extant 1906 Hoffman (a.k.a. Marshall) building, which was designated an ASCE National Historic Civil Engineering Landmark in 2002. The dispiriting history of flat-slab development after the e...