Head Plate Research Articles

Study on the influence of anchor plate parameters on the bearing characteristics of the new large-diameter multi-plate soil anchor and creep property of anchor.

The existing mechanical and grouting anchors mostly use the expansion shell method to form a cavity on the borehole wall, and the cement slurry is poured to form multiple enlarged head plates, but the operation is more difficult and the diameter of the formed plate is smaller. In this paper, a new type of large-diameter multi-plate soil anchor and its reaming cavity forming tool are proposed, which can make the operation easier and form a large-diameter enlarged head plate. In order to study the influence of the diameter of anchor plate, the number of anchor plates and the spacing of anchor plates on the vertical uplift capacity of the large-diameter multi-plate soil anchor, 25 sets of comparative models were established for simulation analysis. The finite difference method of FLAC3D software is used to simulate the model. It is found that when the length of the anchor is 6m and the diameter of the anchor rod body is 150mm, the optimal diameter of the anchor plate of the large diameter multi-plate soil anchor is 590mm, the optimal number of anchor plates is 6, and the optimal anchor plate spacing is 800mm, which means the action range of the anchor plate on the lower soil is about 5 times the diameter of the bolt. When the number of anchor plates is too small or the spacing between anchor plates is too large, the structural advantages of large-diameter multi-plate soil anchor cannot be fully utilized, resulting in a decrease in the ultimate uplift capacity. When the number of anchor plates is too large or the spacing between anchor plates is too small, the stress superposition effect occurs in the soil, and the through shear failure occurs, which leads to the decline of the ultimate uplift capacity. Under the condition that the number of anchor plates and the spacing of anchor plates are fixed, the larger the diameter of the anchor plate is, the larger the ultimate pull-out capacity of the large-diameter multi-plate soil anchor is, the smaller the vertical failure displacement of the anchor head is, but the increase of the uplift capacity is gradually reduced. The creep rate of the new large-diameter multi-plate soil anchor bolt is 0.91mm, and the creep rate of equal-diameter soil anchor bolt is 1.69mm. It is verified that the new large-diameter multi-plate soil anchor can be effectively applied to various projects.

A non‐monophyly of ‘crowned’ Daphnia (Ctenodaphnia) Dybowski et Grochowski, 1895 (Cladocera: Daphniidae): From genomes to morphology

AbstractDaphnia (Crustacea: Cladocera) has been frequently used as a model taxon for studying prey antipredator defences. Among numerous representatives of this genus, there are several taxa within the subgenus Daphnia (Ctenodaphnia) with a morphological innovation unique for these cladocerans, a head plate. In some populations, the margin of this anterior projection of carapace into the head shield is adorned with a remarkable ‘crown of thorns’, which has been shown to be an antipredator adaptation against tadpole shrimps (Notostraca). This structure is phenotypically plastic, dependent on the presence of these omnivorous crustaceans in the respective water bodies. We aimed to evaluate the monophyly of Eurasian ‘crowned’ Daphnia species (i.e., those forming the ‘crown of thorns’ under some circumstance) based on genomic phylogenies and morphology. For this study, we have individually sequenced the genomes of five daphniids, four representing taxa able to form ‘crowns’ (two specimens of different clades of the D. (C.) atkinsoni complex and two specimens of D. (C.) triquetra from distant populations), and D. (C.) mediterranea distantly related to D. (C.) atkinsoni that lacks the head plate. We analysed them along with genomes obtained from GenBank, focusing on either full mitochondrial or partial nuclear datasets (BUSCO). Our main hypothesis on a monophyly of all ‘crowned’ daphnids was rejected. Genomic analyses confirmed existence of two independent lineages able to express this phenotypic trait in the Palaearctic: (1) a monophyletic D. (C.) atkinsoni s. lat. and (2) D. (C.) triquetra, formally redescribed here. These lineages form a well‐supported clade together with several other species lacking a head plate (including D. (C.) mediterranea). Genomic analyses indicate that D. (C.) atkinsoni s. lat. is closely related to D. (C.) tibetana; mitochondrial markers also suggest a close relationship of D. (D.) triquetra with D. (C.) studeri, both D. (C.) tibetana and D. (C.) studeri, are lacking this morphological feature. Molecular clock estimated the time of the differentiation of the major clade containing both ‘crowned Daphnia’ to the Late Mesozoic, confirming an antiquity of the head plate as antipredator defence.

Integration of pH Control into Chi.Bio Reactors and Demonstration with Small-Scale Enzymatic Poly(ethylene terephthalate) Hydrolysis.

Small-scale bioreactors that are affordable and accessible would be of major benefit to the research community. In previous work, an open-source, automated bioreactor system was designed to operate up to the 30 mL scale with online optical monitoring, stirring, and temperature control, and this system, dubbed Chi.Bio, is now commercially available at a cost that is typically 1-2 orders of magnitude less than commercial bioreactors. In this work, we further expand the capabilities of the Chi.Bio system by enabling continuous pH monitoring and control through hardware and software modifications. For hardware modifications, we sourced low-cost, commercial pH circuits and made straightforward modifications to the Chi.Bio head plate to enable continuous pH monitoring. For software integration, we introduced closed-loop feedback control of the pH measured inside the Chi.Bio reactors and integrated a pH-control module into the existing Chi.Bio user interface. We demonstrated the utility of pH control through the small-scale depolymerization of the synthetic polyester, poly(ethylene terephthalate) (PET), using a benchmark cutinase enzyme, and compared this to 250 mL bioreactor hydrolysis reactions. The results in terms of PET conversion and rate, measured both by base addition and product release profiles, are statistically equivalent, with the Chi.Bio system allowing for a 20-fold reduction of purified enzyme required relative to the 250 mL bioreactor setup. Through inexpensive modifications, the ability to conduct pH control in Chi.Bio reactors widens the potential slate of biochemical reactions and biological cultivations for study in this system, and may also be adapted for use in other bioreactor platforms.

The Experimental Design of a Spring Coil Compressor Remover for Automobile

This study examined various types of coil spring compressors in the automobile industry. A coil spring compressor for compressing a coil spring during the assembly of subassemblies of automotive suspension systems, having a head jaw positioned above a base and movable concerning the base. The coil spring compressor is provided with a pair of guide bars suspended from the head plate and on which a slidable carriage is mounted. The carriage carries a pair of compressing assemblies facing each other in vertical positions and positioned at both the upper and lower parts of the coil spring. Each assembly comprises a pair of compressor arms interconnected with each other. Each compressor arm is provided with a jaw mount to which a compressing hook is adjustably attached. The jaws are introduced between a few successive turns of the coil spring by operating handles provided on the compressor arms. The purpose of this design is to be used on various types of suspension disassembly and assembly of vehicles, the tool includes the upper and the lower jaw which by the smooth turning of the screw lowers to compress the coil spring or turns to release the compressed coil spring. The new design was made from mild steel and the tools used for the construction were an electric arc welding machine, power, and hand hacksaws, the bench vice, assorted hammers, vice, etc. The findings indicated that the new design is more efficient than the existing one. It was also recommended that car owners who visit the workshop should insist on the use of the right compression tool in the disassembly and assembly of their suspension systems.

Biomechanical comparison of three fixation strategies for radial head fractures: a biomechanical study.

Second-generation headless compression screws (HCSs) are commonly used for the fixation of small bones and articular fractures. However, there is a lack of biomechanical data regarding the application of such screws to radial head fractures. This study evaluated the mechanical properties of the fixation of radial head fractures using asingle oblique HCS compared with those obtained using a standard locking radial head plate (LRHP) construct and a double cortical screw (DCS) construct. Radial synbone models were used for biomechanical tests of HCS, LRHP, and DCS constructs. All specimens were first cyclically loaded and then loaded to failure. The stiffness for the LRHP group was significantly higher than that for the other two groups, and that for the HCS group was significantly higher than that for the DCS group. The LRHP group had the greatest strength, followed by the HCS group and then the DCS group. The HCS construct demonstrated greater fixation strength than that of the commonly used cortical screws, although the plate group was the most stable. The present study revealed the feasibility of using a single oblique HCS, which has the advantages of being buried, requiring limited wound exposure, and having relatively easy operation, for treating simple radial head fractures.

Design Improvements by Using the Design for Assembly (DFA) Method in Elevator Production

The purpose of this research is to show the benefits to be obtained by redesigning production processes for small and medium-sized enterprises, which aim to grow but cannot develop due to runaway production. In this study, an exemplary approach is presented using the principles of Design for Assembly (DFA) in an enterprise aiming to grow in the elevator industry. Within the scope of the research, the doorframe assembly process of the semi-automatic elevator door, which is the most produced in the elevator industry, was examined. According to this; Design improvement studies were carried out in the assembly processes of the side profiles, head plate, forehead plate, floor plate and their subparts used in the production of the case. In the design improvement, the B&D design efficiency measurement principles were used. As a result of the improvements; The semi-automatic door frame, which is 98 pieces in its current design, has been reduced to 55 pieces with the new design. With the reduction in the number of parts and design changes, the total assembly time was reduced by 33.8% in assembly time. As a result of the improvements, the Design Efficiency has been increased from 8.5% to 12.8%.

Description of the immature of Podisus graziae Brugnera, Roell & Lemaître, 2021 (Heteroptera: Pentatomidae: Asopinae)

As predaceous insects, the Asopinae have a great economic importance. The knowledge about the development of the species is essential for use in biological control programs. However, only 1% of the Neotropical Asopinae species have the immature stages known. In this work we describe the egg and the five nymphal stages of Podisus graziae Brugnera, Roell & Lemaître, 2021 using light and scanning electron microscopy. The results show that P. graziae eggs and nymphs present unique characters which are not observed in other species of the genus and subfamily. As other Podisus species, the egg present long aero-mycropilar processes, however, the chorion and operculum have a ring of minute spine-like projections. As main diagnostic characters of nymphs, the iridescent coloration of head, thorax and abdominal plates, and a pair of yellow spots in the pronotum and anterior region of abdomen are noticed.

Modeling of 3-D thickness distribution of a head plate based on forming process simulation analysis

Modeling of 3-D thickness distribution of a head plate based on forming process simulation analysis

Ecomorphological differences among forest and rock dwelling species of Darevskia Arribas, 1999 (Squamata, Lacertide) in the Elburz Mountains, Iran

Ecological pressure is the major driver of morphological adaptation. Different habitat preferences even among closely related species, often result in the evolution of different body shapes. In the present study, we employed geometric morphometric and principal component analyses (PCA) to compare body shape and head plate morphology among seven species in the genus Darevskia Arribas, 1999 from the Elburz Mountains, Iran that occur in either rocky or forested habitats. The geometric morphometric analysis and the PCA of meristic characters recovered a wide degree of overlap between the rock and forest dwelling species. The PCA of the morphometric characters showed wide separation among the rock and forest dwelling species as well as among some of the rock dwelling species. These results strongly suggest that body shape is correlated with the habitat type whereas head plate morphology and scale meristics are not. Furthermore, the results suggest that the rock dwelling species may be occupying and navigating their microhabitat in different ways. Ecological observations are needed to test this hypothesis.

Unsteady characteristics of lubricating oil in thrust bearing tank under different rotational speeds in pumped storage power station

Oil mist accumulation and leakage in hydropower generator bearings are common. However, they undermine not only the operational safety and stability of the generator but also the balance of living organisms downstream of rivers. Most studies on oil flow patterns are based on steady flow field simulations, which may result in potential errors particularly due to initial and unforeseen velocity increases. The unsteady multiphase flow numerical simulation method was used to calculate the motion behavior of lubricating oil in thrust bearing tanks at different rotating speeds. The variations in lubricating oil flow, pressure distribution characteristics, velocity, temperature, oil level, and vorticity at different times were obtained. The results show that the flow and pressure field distributions in an oil tank are mainly affected by the rotation of the thrust head and mirror plate and by the cooling circulation method, respectively. The lubricating oil motion becomes a function of gravity, centrifugal force, and Coriolis force. The oil surface of the volume fraction exhibited periodic motion around the tank and a climbing movement in the oil-retaining ring and oil slinger. The oil-retaining ring performs well at a speed of 500 rpm; however, minute oil droplets and mist rapidly spread in the tank due to violent oil fluctuations. Large vortices with periodic oil surfaces are also observed in regions with high turbulence intensity owing to shear and centrifugal forces. The method and framework presented can be used to optimize the structural design of thrust bearing assembly and reduce the formation of oil and gas mixtures.

Comparision of predicted and actual treatment outcome based on steiner cephalometric analysis using nemotech software

Social and psychological concerns, improved function, appearance, and self-esteem encourages a patient to pursue Orthodontic treatment, for which extraction may or may not be needed.Conventionally steiner stick analysis or tweed head plate correction is followed to decide extraction during fixed orthodontic treatment for desirable treatment outcome. This study was designed to compare predicted position and angulation of maxillary and mandibular incisor by steiner stick analysis with the actual treatment outcome using memotech software.Sample was taken from our department consisting of pre and post treatment lateral cephalogram of 15 subject with age ranging from 20- 22years. Tracing was done using Nemotech software and values for Steiner’s analysis was obtained, both for, pre and post treatment tracing. Prediction was done by Steiner Stick analysis(SSA) on the pre treatment tracing.The position and angulation of Maxillary and Mandibular incisor was compared between prediction based on SSA and post treatment outcome. The parameters taken were U1-NA Linear and U1-NA angular and L1-NB Linear and L1-NB angular and comparison were made using Paired Student T test.: No significant difference was seen in U1-NA distance in (mm) and angulation(degree) Compared between predicted values(U1-NA- 2.478mm, 20.53 degree) and post treatment outcome (U1-NA-2.80mm, 22.733 degree) , p>0.05. Similarly no significant difference was seen in L1-NB distance (mm) compared between predicted (L1-NB 3.1227mm) and post treatment outcome(3.487 mm), p>0.05. However significant difference was seen for L1-NB angulation between predicted (22.573) and actual post treatment outcome(26.02), p<0.05.: Steiner Stick Analysis overestimated the values for angulation for Mandibular Incisors. This could be attributed to variability in mechanics or small size sample. Further studies should aim at comparisons done in larger sample size.

An increase in spontaneous activity mediates visual habituation.

SUMMARYThe cerebral cortex is spontaneously active, but the function of this ongoing activity remains unclear. To test whether spontaneous activity encodes learned experiences, we measured the response of neuronal populations in mouse primary visual cortex with chronic two-photon calcium imaging during visual habituation to a specific oriented stimulus. We find that, during habituation, spontaneous activity increases in neurons across the full range of orientation selectivity, eventually matching that of evoked levels. This increase in spontaneous activity robustly correlates with the degree of habituation. Moreover, boosting spontaneous activity with two-photon optogenetic stimulation to the levels of visually evoked activity accelerates habituation. Our study shows that cortical spontaneous activity is linked to habituation, and we propose that habituation unfolds by minimizing the difference between spontaneous and stimulus-evoked activity levels. We conclude that baseline spontaneous activity could gate incoming sensory information to the cortex based on the learned experience of the animal.

Chronic co-implantation of ultraflexible neural electrodes and a cranial window.

.Significance: Electrophysiological recording and optical imaging are two prevalent neurotechnologies with complementary strengths, the combined application of which can significantly improve our capacity in deciphering neural circuits. Flexible electrode arrays can support longitudinal optical imaging in the same brain region, but their mechanical flexibility makes surgical preparation challenging. Here, we provide a step-by-step protocol by which an ultraflexible nanoelectronic thread is co-implanted with a cranial window in a single surgery to enable chronic, dual-modal measurements.Aim: The method uses -thick polymer neural electrodes which conform to the site of implantation. The mechanical flexibility of the probe allows bending without breaking and enables long-lasting electrophysiological recordings of single-unit activities and concurrent, high-resolution optical imaging through the cranial window.Approach: The protocol describes methods and procedures to co-implant an ultraflexible electrode array and a glass cranial window in the mouse neocortex. The implantation strategy includes temporary attachment of flexible electrodes to a retractable tungsten-microwire insertion shuttle, craniotomy, stereotaxic insertion of the electrode array, skull fixation of the cranial window and electrode, and installation of a head plate.Results: The resultant implant allows simultaneous interrogation of brain activity both electrophysiologically and optically for several months. Importantly, a variety of optical imaging modalities, including wide-field fluorescent imaging, two-photon microscopy, and functional optical imaging, can be readily applied to the specific brain region where ultraflexible electrodes record from.Conclusions: The protocol describes a method for co-implantation of ultraflexible neural electrodes and a cranial window for chronic, multimodal measurements of brain activity in mice. Device preparation and surgical implantation are described in detail to guide the adaptation of these methods for other flexible neural implants and cranial windows.

Evaluation of meridional thickness distribution of a head plate based on forming process simulation analysis

In FBR plants the head plate constitutes a part of the boundary of the containment vessel (CV), therefore, it is a very important issue if the function as the boundary is maintained or not in the case of severe accident (SA). Buckling and post-buckling behaviors due to pressure loading must be affected by the thickness distribution of the head plate during press forming process. In this paper non-linear finite element simulation analyses assuming press forming process of a head plate are improved after the previous paper and the discussion is made comparing the analysis results with the measured results of thickness distribution of the head plate specimen used for the pressure endurance test. And also, the modelling for finite element analyses of head plates is discussed. In this study, axisymmetric analyses are implemented focused on the thickness distribution along the meridional direction of the head plate.

Evaluation of the partitioned mechanical properties and the hall-petch relationship of cast aluminum alloy cylinder head

In view of the non-uniform distribution of mechanical properties of cast aluminum alloy cylinder head, the mechanical properties evaluation and microstructure heterogeneity of cylinder head were studied. The results showed that the head plate position of the cylinder head has the best mechanical properties and microstructure characterization, followed by the floor plate and the thick partition plate. The mechanical properties of the floor plate position attenuate with increasing temperature. From 23°C to 300°C, the tensile strength and yield strength decrease in the same range, but the break elongation changes most obviously. The mechanical properties and microstructure characterization of cylinder head in-situ sampling satisfy the Hall-Petch relationship. If the required ultimate tensile strength is not less than 255MPa, the upper threshold of the grain size, by considering the error limit of the Hall-Petch relationship, is 603.4μm, and the upper threshold of secondary dendrite arm spacing is 69.1μm. Meanwhile, established the relationship between hardness and yield strength, the average error of the nonlinear model is 4.35%. The prediction accuracy of the nonlinear model is sufficient to meet the actual needs of the engineering.

Effect of Frictional Conditions in Deep Drawing on Formability

This study investigated the stress and strain behavior caused in the forming process via simulation analysis using the finite element method, for suppressing punch shoulder and head plate thickness reduction die shoulder stress concentration by controlling the friction conditions. The following findings were obtained: The thickness of the blank head and punch shoulder decreased with the forming process. Due to the increase in the coefficient of friction with the punch side, the plate thickness reduction ratio decreases, and is the lowest when it is close to non-lubrication; Stress concentration occurs at the die shoulder with forming processing. With the increase in the friction coefficient value, forming limit parameter (FLP) increases slightly, but as it does not reach the limit value of 1, the forming process can be safely performed without mechanical damage; When the formability is comprehensively evaluated using the plate thickness reduction ratio and FLP, the friction coefficient μ = 0.4 to 0.5 is reasonable.

A new method of controlling excavation face balance by using cutter torque under the condition of a small head aperture ratio

When the penetration and head aperture ratio of a cutter head are small, much earth will be clamped between the cutter head and the excavation face. This clamped earth directly balances most of the pressure from the excavation face, instead of the slurry pressure in the head chamber. In this case, some operators of shield machines and large pipe jacking machines in China have begun to use a new method, through which the earth pressure balance state can be controlled by the cutter head torque, instead of the slurry pressure in the head chamber. In this study, we investigate the formation process and stress state of the clamped earth between the cutter head and the excavation face. Contrary to common explanations, our research shows that the cutter head torque is not caused by the “earth–steel” frictional force between the cutter head plate and excavation face. The average frictional force between them can be close to zero in some situations. The cutter head torque is usually caused by an “earth– earth” friction between the clamped earth and excavation face. We also treat the clamped earth as plastic soil, which flows from the excavation face, via the section filled by the clamped earth, to the head chamber. In this way, the relationship among the cutter head torque, earth pressure, and excavated velocity is determined. Results indicate that controlling the cutter head torque is equivalent to controlling the state of the clamped earth. This method can avoid the uncertainty and fluctuation of friction on the shield shell and shield correction.

3D‐Printing with steel of a bolted connection

AbstractAdditive Manufacturing seems promising for the steel construction industry, especially for small components with complex shapes. With Wire‐and‐Arc‐Additive‐Manufacturing (WAAM) a process was found which is fast and cheap compared to other Additive Manufacturing processes for metals. Furthermore, arc‐welding is well known in steel construction industry.Bolted head plates are a common connection. Although they are relatively easy to produce, they are uneconomical in load transfer due to straining of the plates which are subject to bending. This type of connection is predestined for Additive Manufacturing. Rethinking the structure by taking into account the potentials of Additive Manufacturing brings a clear advantage compared to the conventional production. Thus, with a material saving of 60 % the same load capacity of the original flat head plate can be achieved.The paper shows how the new production process WAAM can significantly change the shape of structures on the example of a bolted head plate. Therefore, all steps from the original design to the manufactured structure are demonstrated, including the structure finding by using topology optimization, the manufacturing with different parameters and a first testing of the manufactured structures.

3D‐Printing with Steel ‐ Additive Manufacturing Connections and Structures

AbstractAutomated production is finding its way into fabrication of structural steel. One robot holds attachments (stiffeners, head plates, etc.) to a steel beam or column and another robot produces weld seams. However, welding robots can also be used for additive manufacturing (Wire + Arc Additive Manufacturing, WAAM). The wire electrode serves as printing material. The Institute for Steel Construction and Materials Mechanics in Darmstadt is investigating how typical connecting elements of steel construction can be printed directly on steel beams using Additive Manufacturing with arc welding and robots. Furthermore structural elements like nodal points are printed and even complete structures like columns and a little bridge have been manufactured additively already. The main focus is on determining suitable welding and process parameters. In addition, topology optimization is used to find good structures using a low amount of material. This is possible due to the free design prospects of 3D‐printing. This opens for novel design and production strategies.

Full static resistance of castellated steel beams with hexagonal web openings for blast response predictions

To avoid structural collapses by explosions and terrorist attacks, castellated steel beams (CSBs) could become an alternative to parent steel beams (PSBs) in structures due to high energy absorption capabilities, which offered through a combination of high strength and ductile response. The static resistance function, obtained by either experiments or FE modeling, is considered an important item of data in calculating the dynamic response of a system using Single Degree of Freedom models. This research estimated and promoted the static resistance of CSBs to enhance their ductility and dissipate blast energy through large deformation kinematics. Quasi-static experiments on CSBs were performed to investigate the effect of end connections and different strengthening techniques (closed holes and vertical stiffeners) on the static resistance of CSBs. Load-deflection and strain data were recorded for each specimen up to failure. Moreover, a Finite Element (FE) model was developed and verified against tests. Good matching through all phases of resistance was obtained between the FE and test results. An extensive parametric study was carried out to predict the full static resistance of CSBs under the effect of cross-section geometries. Different ranges of spans were investigated to determine the minimum effective span-to-depth ratio. By providing vertical stiffeners as well as bolted head plate connections, CSBs obtained a larger capability of deformation through the tension membrane stage to resist blast loads under simultaneous high tension and shear forces.