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Funding Information: This work was supported by AI spider silk threading (ASSET) in the AIPSE program of the Academy of Finland under Project 317018. Publisher Copyright: Crown Gel-like matter is used extensively in a wide range of application fields including industrial applications such as the manufactory and assembly of garment and footwear products, soft macro/micro-robotics, medical diagnostics, and drug delivery. However, the manipulation of gel-like matter is very challenging, due to its high deformability, high viscosity, and fast phase changing. In this letter, we propose a novel biomimetic robotic fiber threading approach based on impedance control with force tracking. The highly integrated approach can control the impedance of the fiber during both threading and solidification of the fiber and characterize the mechanical properties of the fabricated fibers in the very same setup without changing parts. The impedance control method has also been adapted in this letter by adding a real-time estimator for continuously estimating the stiffness of the threading force for highly accurate control. The resulted fibers using the proposed approach demonstrates higher performances in all terms of toughness, stiffness, elongation and strength, compared to the traditional velocity controlled fiber fabrication approach.

This essay explores the extent to which residues of the practices inherent in nineteenth-century science lecture-demonstrations from the Royal Institution of Great Britain (RI) are evident in contemporary forms of Science Museum Group (SMG) Explainer presentations. The discipline of Performance Studies offers a number of models to discuss such a consideration and this essay draws particularly on the connected, transgenerational theories of vertical transmission, embodied knowledge and intertheatricality. Specifically, the focus is on three notable scientists, selected here for their particular influence on the lecture-demonstration practices at the RI during the nineteenth century: Humphry Davy, Michael Faraday and John Tyndall. It suggests that aspects of their embodied performances in the lecture theatre have been transmitted through subsequent generations of RI practitioners. Extending this transmission, via specific events in 1954 that led to Science Museum Guide Lecturers observing RI practices, it suggests that these practices were then inherited and passed down through generations of lecturing and explaining staff at the museum.

We propose a two-step hydrogen-ion implantation approach for realizing crystalline-defect-free Si1-xGex channels for potential use in gate-all-around field-effect-transistors beyond the 3 nm transistor-design rule. A dislocation sink was created in a projected range of ion implantation 100 and 200 nm above the strain-relaxed Si0.7Ge0.3 layer and Si substrate interface using two-step H+ -ion implantation. Doses of 5 × 1015 and 2 × 1015 atoms/cm2 were used at 100 and 200 nm, respectively, above the interface, and post-annealing was performed at 800 °C for 30 min. The two-step implantation annihilated the misfit and threading dislocations near the relaxed Si0.7Ge0.3/Si interface. The annihilation efficiency strongly depended on the location and second ion dose of the implantation: the maximum annihilation efficiency was obtained at 100 and 200 nm above the interface with multiple H+-ion doses of 5 × and 2 × 1015 atoms/cm2.

INTRODUCTION One of the most frequently performed anti-aging surgical procedures is thread facelift. Since the 2010s, thread lifts using absorbable polydioxanone (PDO) thread were developed and have become increasingly popular. This research aims to identify the changes in and the mechanisms of absorbable thread-lifting components, namely, PDO (polydioxanone) and PCL (polycaprolactone), with varied absorption periods in the body. METHODS Four different types of threads, namely, single-stranded thread, 4-stranded thread, 12-stranded thread, and barbed Cog thread, were used for each component. Histological changes in the thread and neighboring tissue of rat model were investigated for 2-week interval, and PCR was conducted for genes related to fibroblast proliferation including type 1α1 collagen, type 3α1 collagen, transforming growth factor beta 1 (TGF-β1). RESULTS An increase in the collagen formation in all types of PDO and PCL groups was observed during the first 12 weeks and decreased afterward. Collagen formation decreased later in the PCL thread group significantly than the POD group. PCL thread remained logner in the tissue for over a year regarding POD requiring around 24 weeks of absorption-degradation. A larger surface area between the thread and the tissue induces a greater response in the tissue, resulting in an increase in inflammatory cells, myofibroblasts, and fibroblasts. Results showed a similar pattern of increase in type 1α1 collagen and TGF-β in the PDO thread group. This suggests that TGF-β signal transduction leads to fibroblast proliferation that stimulates collagen formation and tissue re-formation. In contrast, only type 3α1 collagen increased in the PCL thread group. CONCLUSION More collagen formation and tissue responses are induced by PCL thread, remaining longer in the tissue than PDO, leading to more tissue tightening effects that is one of the most important points of face lifting. Morphological comparison of threads shows that not only an increase in surface area between thread and tissue but also multi-strand increase tissue response, which in turn increases tissue maintenance effects.

In this paper, a numerical analysis of the cold thread-rolling process using flat dies is presented as a function of the die geometry design. Five die geometries with different threading and finishing ratios were modelled to induce different screw deformation rates. An analytical method was proposed by the authors to design die geometries as a function of screw roll rotation. Screw geometry accuracy, induced stress, and die wear were selected to compare the tested geometries. The results showed that three screw rotations in the threading step were sufficient to guarantee good geometry accuracy. Moreover, the results highlighted that die wear is the most affected parameter among all the tested geometries. Finally, a new solution was proposed by the authors to obtain uniform wear and reduce the die length.

In the present research, measurement of residual stress induced during turning and threading operations for the fabrication of two types of pin profiled friction stir processing/welding (FSP/FSW) tools, i.e. cylindrical profiled pin tool and cylindrical threaded profiled pin tool, is being dealt with. Workpiece was chosen to be H13 tool steel with a diameter of 22[Formula: see text]mm and 110[Formula: see text]mm length. Turning and threading was done on CNC machine tools using CNMG 12404-THM uncoated tungsten carbide cutting tool. For residual stress measurement of the workpieces, an XRD-based Pulsetec[Formula: see text]-X360n portable residual stress analyzer setup was used. The experimental results show that the cylindrical pin profile tool had a compressive residual stress of [Formula: see text][Formula: see text]MPa and compressive residual shear stress of [Formula: see text][Formula: see text]MPa, while the cylindrical threaded pin profile tool had a compressive residual stress of [Formula: see text][Formula: see text]MPa (51.8% more) and compressive residual shear stress of [Formula: see text][Formula: see text]MPa (40% less). It has been concluded that due to threading operation on the cylindrical threaded pin profile, the value of residual stress is more in it, and since the stress is compressive in nature, it would have a better positive impact while doing FSP/FSW than that of the cylindrical profiled pin tool.

International audience; A family of cyclodextrins functionalized with zero, one, two, or six amines was shown to control the rate of their threading and dethreading on a molecular axle depending on the pH and their substitution pattern. The originality of this system lies in the rate control of the switch by operating the stimulus directly on the macrocycle.

‘Interoperability’ means the ability for two different and independent information and communication technology (ICT) systems to exchange information and use that information. Whether or to what ex...

A model of the magnitude of the stresses of the tip of the cutting blades of a thread-forming tool based on the theory of a homogeneous body is proposed. A model of second-order materials is considered. A description of the stress state is given using two stress tensors independent of each other.

Aspects of thread manufacturing used in downhole rod pumps are considered. Technological defects of distortion of lateral surfaces of a thread profile arising in the course of processing on CNC machines are described, and the factors which most influence formation of these defects are established. The influence of profile defects on the reliability of the threaded connection during the operation of rod pumps is analyzed, as well as the research on the dynamics and oscillations of machine systems is analyzed. With the performed analysis the mathematical model of real techn ological system in the course of machining process is created and investigated. The main technological factors that have the greatest influence on the occurrence of error in the shape of the thread surface are identified. With the help of software for analysis of dynamic systems, the necessarily calculations were performed and the behavior of the dynamic system in the process of forming the thread profile was considered. Based on the analysis of the obtained results, a system for managing the parameters of the technological process of threading and technological solutions formulated. The introduction of which had a positive impact on the stability of the machining process and reduce the frequency of the above defect. Розглянуто аспекти виготовлення різьблень, які використовуються в свердловинних штангових насосах. Описано технологічні дефекти спотворення бокових поверхонь профіля різьблення, що виникають в процесі обробки на верстатах з ЧПК, та встановлено фактори, які найбільш впливають на утворення цих дефектів. Проаналізовано вплив дефектів профілю на надійність різьбового з’єднання в процесі експлуатації штангових насосів, а також проаналізовано дослідження з питань динаміки й коливань верстатних систем. Завдяки виконаного аналізу створено і досліджено математичну модель реальної технологічної системи, яка використовується в процесі обробки різьбової поверхні. Встановлено основні технологічні фактори, які мають найбільший вплив на виникнення похибки форми різьбової поверхні. За допомогою програмного забезпечення для дослідження динамічних систем виконано необхідні розрахунки та розглянуто поведінка системи Верстат-Пристосування-Заготовка-Інструмент в процесі формування профілю різьби. На підставі аналізу отриманих результатів розроблена система керування параметрами технологічного процесу обробки різьбової поверхні та сформульовані технологічні рішення, впровадження яких мало позитивний вплив на стабільність якості процесу обробки та на зменшення частоти появи розглянутого вище дефекту точності форми профілю різьблення та підвищило ефективність виробництва.

In this paper, the thread turning of aluminum 7075-T6 alloy is studied using micro-hole textured solid-lubricant embedded carbide inserts. The primary focus of this work is to enhance the performance of the thread turning process for producing high quality threaded parts. To achieve this, micro-holes were generated by laser micro-machining on the rake face of tools and then, MoS2 and CNT (carbon nanotube) solid-lubricants were embedded into micro-holes. The effects of micro-holes and solid-lubrication on the performance of the thread turning process were examined using traditional tool ( T0), micro-hole textured tool ( T1), micro-hole textured MoS2 embedded tool ( T2), and micro-hole textured CNT embedded tool ( T3). In this study, cutting forces, chip-tool contact length, built-up edge (BUE), surface roughness, and operating cost were investigated. The influence of micro-hole generation on the mechanical strength of cutting inserts was evaluated using the finite element method. The results showed that the fabrication of the micro-holes on the rake surface of cutting inserts has no significant effect on the mechanical strength of the tools. The comparisons of our method with traditional tools demonstrated that the cutting performance improved in the threading process. Our results reveal that the main cutting force, radial thrust force, surface roughness, built-up edge, and chip-tool contact length reduced 37.1%, 40.9%, 37.9%, 58.3%, and 38.2%, respectively, as T3 tools are applied in this process. A cost analysis, based on estimated tooling costs, showed that the T3 tool can yield an 18% reduction in overall operating cost.

In this paper, the parameters of microtextured tools were studied in the threading of aluminum 7075-T6 alloy. The primary focus of this work is to optimize the parameters of microtextured tools usi...

Thick epitaxial (3-15 microns) GaN power switching devices are known to contain a high density of crystal defects, and especially threading dislocations in the epitaxial layer. The impact of these defects on device performance and reliability is a topic of ongoing research. This paper presents state-of-the-art methods for analyzing threading dislocation density, growth, and quantification of their impact on leakage current, blocking voltage, and peak E field. The effects of substrate type, epitaxial thickness, and processing techniques on dislocation density have been investigated to provide a roadmap for design and performance optimization of switching two terminal devices. Experimental and simulated data are used in conjunction to model dislocation impact on electrical performance characteristics and to identify techniques to minimize defect density. The experimental results have been achieved for 3 and 10 micron thick epitaxy as well as initial results for 15 micron epitaxy. The substrate was bulk GaN, and the epitaxy was grown by HPVPE by Kyma Corporation. The DMOS test structure investigated showed state of the art current voltage characteristics for a 10 micron n- epitaxy. Significant deviations were observed between the measured doping profile and the simulated profile, using a critical field of 3 MV/cm. For the DMOS device with epi doping of 8 × 1015 𝑐𝑚−3 and epi thickness of 8 𝜇𝑚. The device breaks down at approximately 2020 𝑉. At 2000 𝑉, the peak field is roughly 3.11 𝑀𝑉/𝑐𝑚. For a device with epi doping of 8 × 1015 𝑐𝑚−3 and epi thickness of 15 𝜇𝑚. The device breaks down at approximately 3020 𝑉. At 3000 𝑉, the peak field is roughly 3.14 𝑀𝑉/𝑐𝑚. The observed trend is significant since it shows that by increasing the epi thickness, also results in an increase in the peak field. For thin GaN epi of 3 microns, a peak breakdown field of 2.77 MV/cm was measured. These three date points will allow one to determine a relationship between peak critical field and epi thickness, which is a major requirement for designing vertical GaN high voltage switches. We report images from transmission x-ray topographs and TEM investigations as well as the correlation with critical breakdown field measurements. The transmission x-ray topograph shows that the GaN is characterized by a nearly uniform distribution of strain centers which are likely bundles of threading screw and edge dislocations. Strain free centers are then regions of relatively low dislocation densities. The threading dislocations are part of dislocation loops which are present in the GaN substrate and migrate through the interface. The cross-sectional TEM image shows partial dislocation loops through the thickness of the GaN sample. Figure: X-Ray Topography of GaN/GaN showing a nearly uniform distribution of strain centers. The Grazing incidence topograph is similar to the transmission image, the grazing image also shows the nearly uniform distribution of strain centers. The X ray image shows that individual threading dislocations are not resolved showing a relatively low dislocation density in those regions. Figure 1

In this study, laboratory experiments are conducted to assess the effects of a set of novel ring-type collars and prevalent spiral threading around a circular pier on scouring in a clear-water flow...

Adding small amounts of ring polymers to a matrix of their linear counterparts is known to increase the zero-shear-rate viscosity because of linear-ring threading. Uniaxial extensional rheology measurements show that, unlike its pure linear and ring constituents, the blend exhibits an overshoot in the stress growth coefficient. By combining these measurements with ex-situ small-angle neutron scattering and nonequilibrium molecular dynamics simulations, this overshoot is shown to be driven by a transient threading–unthreading transition of rings embedded within the linear entanglement network. Prior to unthreading, embedded rings deform affinely with the linear entanglement network and produce a measurably stronger elongation of the linear chains in the blend compared to the pure linear melt. Thus, rings uniquely alter the mechanisms of transient elongation in linear polymers.

Marvell ThunderX3 is the third-generation Arm-based server processor from Marvell. This article describes the architecture of ThunderX3, going into details of core microarchitecture. ThunderX3 is distinctive among mainstream processors in supporting four SMT threads. The article describes the threading microarchitecture of ThunderX3 and highlights threading benefits. The article also touches on the on-chip interconnect and L3-cache and the power management subsystem. Initial benchmark results from silicon show 30%+ single thread and up to 3X socket level performance gains over the prior generation resulting in industry-leading single thread and socket level performance.

The multiple signal classification algorithm (MUSICAL) is a statistical super-resolution technique for wide-field fluorescence microscopy. Although MUSICAL has several advantages, such as its high resolution, its low computational performance has limited its exploitation. This paper aims to analyze the performance and scalability of MUSICAL for improving its low computational performance. We first optimize MUSICAL for performance analysis by using the latest high-performance computing libraries and parallel programming techniques. Thereafter, we provide insights into MUSICAL’s performance bottlenecks. Based on the insights, we develop a new parallel MUSICAL in C++ using Intel Threading Building Blocks and the Intel Math Kernel Library. Our experimental results show that our new parallel MUSICAL achieves a speed-up of up to 30.36x on a commodity machine with 32 cores with an efficiency of 94.88%. The experimental results also show that our new parallel MUSICAL outperforms the previous versions of MUSICAL in Matlab, Java, and Python by 30.43x, 2.63x, and 1.69x, respectively, on commodity machines.

Threading has become quite popular in recent years as an alternative to tapping or other forms of threading because of diversity and complexity of parts and flexibility of the process in industries such as biomedical applications, aerospace and die-mold manufacturing. However threading is one of the complex and critical operations due to its tool geometry. To analyze the threading parameters by means of design of experiment concept wit response surface methodology. The full factorial design is used for experimental design. The three levels of spindle speed and depth of cut are used as an input parameter. Similarly responses are material removal rate, surface roughness and forces such as feed force, trust force and cutting force during threading operation. The main objective of this study is to evaluate the difference between the Square thread and pilot v grooved square thread to maximize the surface finish of threading. And also to determine the responses, such as Material Removal Rate (MRR), Surface Roughness, and Forces for square thread and the pilot grooved square thread. Based on the analysis pilot v grooved square thread is better than square thread. As a result in Square Thread and pilot v grooved square thread responses such as Feed Force, Thrust Force, Cutting Force, and MRR and is high. Surface Roughness is high only in Square Thread compared with pilot v grooved square Thread.

The research paper presents the theoretical studies results of noise generation during workpieces processing on threading and spline shaft milling machines. It is proposed the analytical dependence determining the sound pressure and sound power for various acoustic models of the noise sources with grounding conditions of the cutting tool, workpieces and their geometric dimensions.

The article presents the results of analysis and research in the direction of improving technological equipment for internal threading of parts in a flexible automated production. Methods for assessing the operational and technological reliability of a flexible manufacturing module (FMM) of thread processing are considered, which can be used as the basis for the developed method of synthesis of its elements. It is proposed to consider the technological system of the flexible manufacturing module (FMM) of thread processing as a system in which transitions from state to state occur under the action of the simplest flows with parameters of the transition probabilities of a continuous Markov chain. The developed mathematical model describing the state of the FMM taking into account the failures of the functioning of its elements, parametric failures, as well as taking into account the recovery after these types of failures, makes it possible to reflect the influence on the operation of the module of the parameters of the flows of failures and restorations of the tool, machine tool, fixture, loading device. The solution of the obtained systems of equations of final probabilities allows for given (or experimentally obtained) intensities of failure streams (functioning and parametric) for FMM threading to obtain the values of the probability of failure–free operation, as well as the probabilities of finding the system in an inoperative state due to corresponding failures. The measures taken make it possible to solve the synthesis problem at the level of structural and layout optimization, so that at the stage of parametric synthesis to determine the elements that are vulnerable according to the developed criterion, the improvement of which will lead to the creation of the most efficient system.

The development of residual stresses in tools due to machining is a widely known fact and these residual stresses can often lead to unwanted modifications in tool life. Turning, tapering and threading are extensively used in various manufacturing processes and they are specially used for the machining of different types of Friction stir welding/ processing (FSW/FSP) tool pin profiles. FSP being a solid-state process undergoes high levels of plastic deformation and so tool pins having extreme values of residual stresses may pose a problem for longevity of tool life. In this research, turning, tapering, and threading operations were conducted to produce two types of FSW/FSP tool pin profiles namely taper cylindrical and taper threaded. H13 tool steel is extensively used to produce tools FSW/FSP and hence it was chosen. H13 tool steel workpiece with 110 mm length and 22 mm diameter was taken as the workpiece and machining operations were performed to produce FSW/FSP tool on CNC Lathe machine. The objective of the present study is to establish the values of residual stresses developed in both tool pin profiles by utilizing the PulsetecµX-360n portable stress analyzer setup. The results that are achieved are then compared for both the pin profiles – taper cylindrical and taper threaded. It was observed that sigma(x) and tau (xy) residual stresses, both are higher in the case of taper threaded pin, and tau (xy) value is significantly higher for taper threaded.

In the article the principles of construction of modern thread-cutting equipment based on mechanisms of parallel structures are considered. The optimal structure was identified and combined with a variant of the combination of MPS with the ability to simultaneously change the length of the rods and the coordinates of reference hinge, ensuring the implementation of a significant number of technological methods in the same workplace for one installation details. The principle of operation of the resulting hybrid thread-cutting machine with a combined MPS of a modular construction in which the executive body can perform a complex spatial movement is described. Based on morphological analysis and structural-layout synthesis, followed by optimization according to the criterion of reliability and economic efficiency, the hybrid layout of a six-spindle thread-cutting machine with MPS. The design of a precast plastically deforming tap of increased resistance is presented due to the possibility of multiple regrindings by shortening the worn-out section of the working part. The measures taken provide high performance, accuracy and quality of the obtained small-sized threads.

A novel approach to efficient and selective construction of [4]rotaxane was proposed to demonstrate the superiority of H-bonded azo-macrocycles in forging higher order rotaxanes. The single crystal structure reveals the importance of the interplay of multiple non-covalent bonding interactions, particularly π-stacking interactions, in stabilizing the host-guest complex. This may open an avenue to the synthesis of oligomeric mechanically interlocked molecules containing fewer stations but more rings.

In case of conical worm production by conventional thread grinder, the fluctuation in angular velocity causes thread error. One possible way to eliminate the pitch error at the conical screw surface machining by shaft displacement is to design a drive pin that provides a constant pitch. In the course of our research, the examination of the machining of the conical worm surfaces by apex adjustment to eliminate the pitch fluctuation problem was carried out as a generalization of studies simulated with trigonometric relations in a particular case. The investigation was continued in a constructive geometric way with the aim of exploring universal mathematical relations in explicit forms in the mathematical kinematic model instead of the point series of the driver pin creator curve calculated in a given occurrence. The developed method makes exact design of the correct threading possible as a function of angular rotation in motion transfer under the given technology conditions, and thus expands the mathematical toolbar for innovative engineering design. Here we introduce the constructive geometric path supported by the algebraic toolbar, which also required affine and projective geometric relations in developing a solution that meets freely chosen expectations.

In this study, threading process with HSS taps was applied to Al 5083 H116 aluminium alloy, which is characterized by its ballistic properties and high corrosion resistance. Differences between screw crest and root dimensions, of the standard screw with calculated theoretically screw with the threads was examined in terms of cutting speed and tap geometry. The experiments were carried out in dry conditions with cutting speeds of 2, 4 and 8 m/min. The screws formed were cut in the direction of their axes on the electrical discharge machine and the sections obtained were viewed with an optical microscope. These images were transferred to the computer-aided design program and necessary measurements were made. As a result of the measurements, it has been observed that the use of helix angle taps in tapping Al 5083 H116 aluminium alloy enables the screw profiles to appear relatively smooth and to obtain results closest to the standard values.

Mono- or few-layer sheets of covalent organic frameworks (COFs) represent an attractive platform of two-dimensional materials that hold promise for tailor-made functionality and pores, through judicious design of the COF building blocks. But although a wide variety of layered COFs have been synthesized, cleaving their interlayer stacking to obtain COF sheets of uniform thickness has remained challenging. Here, we have partitioned the interlayer space in COFs by incorporating pseudorotaxane units into their backbones. Macrocyclic hosts based on crown ethers were embedded into either a ditopic or a tetratopic acylhydrazide building block. Reaction with a tritopic aldehyde linker led to the formation of acylhydrazone-based layered COFs in which one basal plane is composed of either one layer, in the case of the ditopic macrocyclic component, or two adjacent layers covalently held together by its tetratopic counterpart. When a viologen threading unit is introduced, the formation of a host-guest complex facilitates the self-exfoliation of the COFs into crystalline monolayers or bilayers, respectively.

Thread profiles can be considered as mechanical components which contributed to improving the evolution of machines and devices throughout all the history of man. The great importance of using threaded components, in industries and everyday life, is related to the versatility that allows the assembly and disassembly of components exceptionally quickly. Basically, since its invention, the threading tool has been developed, and its geometry has been optimised. Besides, new materials for tooling and coatings have been developed, allowing a significant evolution in the threading process. Thus, this article provides a review, demonstrating the evolution and the main studies in threading processes in the last 20 years, showing the main results obtained and the influence of threading in manufacturing processes. The traditional threading operations such as machining and forming tapping were contextualised, showing the main research with the advances generated in these processes. Furthermore, special internal threading processes were also revised, demonstrating the current developments and their gaps for new studies. Finally, based on this review are proposed lines of research, considering the shortcomings of the contemporary and revised works, that can increase the number of technical information for all threading processes, optimising the current way of making threads.

In this paper, the thread turning of aluminum 7075 aerospace alloy is studied using microtextured carbide cutting inserts. The main target of this research work is to optimize the parameters of mic...

We present the results of a transmission electron microscopy and X-ray diffractometry investigation of AlN/c-Al2O3 templates with GaN ultrathin insertions grown by plasma-assisted molecular beam epitaxy. It has been shown that AlN buffer layers with faceted surface morphology provide a greater threading dislocation density reduction than smooth layers. The filtering effect of GaN ultrathin insertions has been confirmed.

A new process for the fabrication of double positioning boundary (DPB) free 3C-SiC was demonstrated by utilizing the threading screw dislocations of 6H-SiC, using the following two steps: (1) forma...

This article presents a set of performance metrics, test methods, and associated artifacts to help progress the development and deployment of robotic assembly systems. The designs for three task board artifacts that replicate small part insertion and fastening operations such as threading, snap fitting, and meshing with standard screws, nuts, washers, gears, electrical connectors, belt drives, and wiring are presented. To support the evaluation of robotic assembly and disassembly operations, benchmarking protocols and performance metrics are presented that leverage these task boards. Finally, robot competitions are discussed as use cases for these task boards.

Pedicle screw fixation is a fundamental surgical procedure which requires high accuracy and strength from the surgeon who may be exposed to uncomfortable postures and muscular fatigue. The objective of this paper is to propose a novel approach to robot-aided pedicle screw fixation based on a Surgeon-Robot Shared control that makes the tapping procedure, i.e. threading the patients pedicle, semi-autonomous. The surgeon continues to have a full control over the surgical intervention by i) accurately move the robot end-effector using a hands-on control interface, i.e. the surgical tapper, along a pre-planned axis, ii) continuously controlling the forces exerted onto the patient spine during the tapping phase, iii) modulating the torque about the tapping axis by adequately tuning the tool-bone interaction force along the same axis. Furthermore, the procedure appears to be more comfortable and less tiring for the surgeon. The proposed approach was tested on eight subjects who were asked to perform the tapping procedure onto an anthropomorphic spine phantom. A comparative analysis among the proposed approach and the ones typically adopted in literature to perform pedicle screw placement was carried out. The experimental results demonstrated that proposed approach, with respect to the traditional robot-aided procedure, guarantees comparable accuracy and efficiency in the screw placement and lower fatigue and more comfortable postures for the surgeon.

During internal threading, small alterations in cutting parameters, tool geometry, or process characteristics produce considerable effects on torque and temperature behavior. Understanding these effects is critical to the design and development of new taps. In this work, the torque behavior for a tap operation is evaluated as a function of the number of threads, tool manufacturer, and angle of the taper region of the tool. The chip–tool interface temperature was analyzed, considering the influence of cutting speed and number of threads. Experimental tests were carried out using M10x1.5 taps and cutting speeds of 10 m/min and 25 m/min. Taps with two different geometries were considered in this analysis. The results show a difference in the distribution of the torque along the threads of the conical part between the tools. The presence of adhered material increased the torque during the reverse stage. The torque during the reverse stage for a tap with a damaged tooth was approximately 50% of the torque during the cutting stage. The temperature showed an increase with the number of threads stabilizing between the fourth and fifth threads and increasing again in the sixth filled due to adhesion of workpiece material.

Molecular motors transform external energy input into directional motions and offer exquisite precision for nano-scale manipulations. In order to make full use of molecular motor capacities, their directional motions need to be transmitted and used for powering downstream molecular events – a current great challenge for molecular engineers. Here we present a macrocyclic molecular motor structure able to perform repetitive molecular threading of a flexible polyethylene glycol chain through the macrocycle. This mechanical threading event is actively powered by the motor motions and leads to a direct translation of the unidirectional motor rotation into an unidirectional translation motion (chain versus ring). The step by step mechanism of the active mechanical threading is elucidated and also the actual threading step is identified as a combined helix inversion and threading event. The here established molecular machine function resembles the crucial step of macroscopic weaving or sewing processes and therefore offers a first entry point for realizing a “molecular knitting” counterpart.

Fasteners of aircraft gas turbine engines are made of heat-resistant steels and alloys and are operated in intensive conditions under the action of high temperatures. For ensuring reliability, the connecting elements of aircraft engines are made of heat-resistant alloy steels. But under the influence of an aggressive environment, these elements are destroyed, resulting in problems during repairs. The structure of the material of fasteners during the threaded connection by cutting and plastic deformation is considered. The concentration of stresses in the thread plane depends on the density of dislocations, and the depth of corrosion penetration on the outer surfaces of the thread reaches 100 μm. It is proposed to introduce additional heat treatment of parts to improve the physical and mechanical characteristics of the alloy. After additional heat treatment, the σ-phase plates dissolve and prevent the development of microcracks. It is proved that the density of material dislocations in the state of delivery reaches critical values, but the introduction of additional heat treatment allows to increase the performance of parts made of alloy HX – Alloy Type 66Ni-17Cr regardless of the method of threading. Prerequisites for the rational selection of heat treatment modes have been developed, which provide the best mechanical and technological characteristics and the necessary structure of the materials used.

We demonstrate the first reported integration of III-V waveguides (GaAs/Al0.4Ga0.6As) with SiN x waveguides via heteroepitaxial III-V-on-silicon growth. We achieve efficient optical coupling (-2.5 dB loss/transition) at 1550 nm and low threading dislocation density $(4\times 10^{6}\text{cm}^{-2})$ , suitable for fabrication of high-performance optoelectronic devices. © 2021 Massachusetts Institute of Technology

This paper examines the feasibility of roll-threading superelastic Cu-Al-Mn shape memory allow (SMA) rods. The key idea behind this study was to perform roll-threading between quenching and...

Abrasive material removal processes are quite challenging due to high temperatures and power requirements. To achieve quality products, unwanted material removal is required from the base processed material. In the process of removing unwanted material from the workpieces, different operations are involved such as threading, grinding, and turning operations. The main parameters of the material removal process are feed, speed, and depth of cut. During the material removal process, heat is generated from the workpiece as well as tool. Therefore, time to time, lubrication is required to tackle with the problems that rise from generation of heat. Minimum quantity lubrication is an alternate of general cooling systems to protect the environment as well as human health. In the present investigation, attempt has been made to explore the surface roughness, grinding forces, specific grinding energy, grinding temperature, and G ratio in MQL grinding of AISI 52100 steel. The three input variables are considered in this investigation, namely vegetable oils, air pressure, and an ionic fluid. Better results have been attained with the MQL grinding by using coconut oil under different parameters. Signal-to-noise (S/N) ratio as per Taguchi design revealed MQL as significant parameters for surface roughness, whereas feed can be set within the range. Taguchi optimized conditions were validated through multiple response optimization using desirability function.

We compare ~1.7 eV GaAsP top cells grown on GaP/Si templates with different GaAs y P 1-y /GaP buffer layer doping, either unintentionally-doped (UID) or Si-doped (n-type). Unlike our previous work showing 2.7× higher threading dislocation density (TDD) with n-type doping [1], we observed almost no change in TDD between GaAsP top cells grown on UID-buffers or n-buffers with our improved n-GaP buffer design. Similar GaAsP top cell device performance was achieved on UID- and n-buffers with AM1.5G efficiencies of 16.82% and 16.35%, respectively, despite TDD approaching 1×107 cm-2.

3D printing, as a rapid prototyping technique, usually fabricates objects that are difficult to modify physically. This paper presents FlexTruss, a design and construction pipeline based on the assembly of modularized truss-shaped objects fabricated with conventional 3D printers and assembled by threading. To create an end-to-end system, a parametric design tool with an optimal Euler path calculation method is developed, which can support both inverse and forward design workflow and multi-material construction of modular parts. In addition, the assembly of truss modules by threading is evaluated with a series of application cases to demonstrate the affordance of FlexTruss. We believe that FlexTruss extends the design space of 3D printing beyond typically hard and fixed forms, and it will provide new capabilities for designers and researchers to explore the use of such flexible truss structures in human-object interaction.

Modern industry faces a great challenge: the production of consumer goods based on a triangle comprising low costs, low production time and high quality. The optimisation of modern manufacturing processes should seek not only the reduction of manufacturing time but also the reduction of mineral resources and electric energy consumption. In the context of metalworking, considering tapping processes, studies on the use of minimum quantity of lubricant are minimal and scarce. Hence, this study deals with the application of minimum quantity of lubricant and emulsion to the processes of form and machine tapping. To this end, 7075-T651 aluminium alloy workpieces were threaded using both tapping processes at three cutting/forming speeds. M10 threads with a pitch of 1.5 mm were considered the standard profile. Torque and thrust force were monitored, and three threading heads were employed in the experimental tapping tests. According to the results, it can be concluded that the best option was to use minimum quantity of lubricant in order to reduce environmental impact, given its efficient disposal of fluids and compatibility with Softsynchro threading heads, which kept both torque and axial force close to the mean values. Furthermore, this threading head model was also the best for reducing the manufacturing time of the threads.

Calix[6]arenes disubstituted at the methylene bridges, which are stable in the cone or 1, 2, 3- alternate conformation, form pseudorotaxanes with dialkylammonium axles. The cone-wheel based pseudorotaxanes are 10-100 times more stable than those obtained with the native conformationally- mobile calix[6]arene wheel, as a consequence of their higher degree of preorganization. The threading of conformationally stable 1, 2, 3- alternate-calix[6]arenes is unprecedented in the literature. Therefore, very peculiar NMR features are here evidenced for this threading process involving the less symmetrical 1, 2, 3-alternate calix[6]arene conformation, which implies a peculiar rototranslation motion of the axle.

In this work, a four-terminal AlxGa1-xAs/CuInGaSe2 tandem structure has been proposed by analytical model. To develop this model, the real experimental data for CIGS and AlxGa1-xAs cells has been used. Conversion efficiency of optimized Al0.42Ga0.58As/CuInGaSe2 tandem solar cell achieved to 37.1%. Our model estimates the optimum bandgap of AlxGa1-xAs as top cell is in the range of 1.85–2 eV. The optimized thickness of Al0.31Ga0.69As in tandem structure is 5 μm, which decreases to 0.5 μm by light trapping technique. Moreover, we extended our model by the consideration of threading dislocation density in AlxGa1-xAs layer.

Fitting products of different dimensions and design geometries are used in natural gas pipelines, water supply systems, fire installations, machinery equipment and in the aviation and automotive industries. This study aims to investigate the machinability of Al 6061-T6 fittings, which are widely used in the aerospace and automotive industries. In an endeavor to produce reliable and healthy installation systems, Al 6061 material was reinforced with 10 % copper and 316L stainless steel powder in order to increase its corrosion resistance and improve its mechanical properties for sustainable production. These new materials were threaded using a ½ BSP (British Standard Pipe) tap tool via the Taguchi L9 method. Different materials, heat treatments and spindle speeds were used during this manufacturing process. The effects of these manufacturing parameters on the total power dissipated Ptotal were calculated using variance analysis (ANOVA). According to these results, the most effective parameter was the heat treatment type (44.9 %), followed by the material type (30.6 %) and the rpm (19.9 %). It was observed that these aluminum materials can be threaded using 30 to 40 % lower energy consumption compared to cast iron. In addition, the aluminum alloy fitting materials achieved higher hardness than the cast iron fittings.