Large Bumps Research Articles

An off-energy multipole kicker injection scheme designed with an acceptance analysis method for a diffraction-limited storage ring

Diffraction-limited storage rings (DLSRs) have restricted dynamic apertures (DAs) due to their ultralow emittances and very strong nonlinearity. Off-energy multipole kicker injection (MKI) scheme, in which off-energy beam is injected onto the corresponding off-energy orbit, can reduce the requirement of DAs. However, it requires relatively large energy acceptance and high dispersion bumps. For a DLSR lattice with relatively large energy acceptance and off-momentum DAs, off-energy beam can be injected into the off-momentum DA but with an additional offset from the off-energy closed orbit to increase the total offset of the injected beam from the on-energy closed orbit, which is favorable to the application of the off-energy MKI. In this paper, such an off-energy MKI is designed for a DLSR, and an acceptance analysis method based on 6D particle tracking is utilized to design and optimize this injection scheme. Detailed simulation is carried out, and the results demonstrate the feasibility of this injection scheme.

Potential Power Output from Vehicle Suspension Energy Harvesting Given Bumpy and Random-Surfaced Roads

The energy efficiency of vehicles is a crucial challenge relating to sustainable energy preservation and regeneration methods. Regenerative breaking has proven feasible, and there is interest in whether harvesting energy from a vehicle’s suspension is similarly feasible. We here provide methods for estimating the amount of power that can be regenerated from the suspension for given vehicle and road parameters. We show that a reasonable road model is a generalised Gaussian process known as AR(1). Using this model, we can derive the key equation used in the ISO 8608 standard for measuring road roughness, such that the AR(1) parameters can be related to the measured road roughness data. We find that the road roughness coefficient of ISO 8608 and the diffusion coefficient of the AR(1) road are equal up to a factor. We provide an analytical expression for the maximum amount of power that can be generated for given road and car parameters, derived via Fourier analysis. We further model harvesting from large bumps using Simulink. These results help to estimate the potential power output given the measured road data.

Nonlinear analysis and control with nonlinear driving terms for small-emittance storage ring

Storage rings that use the hybrid multi-bend achromat (MBA) lattice concept [1] have been realized. The main characteristics of hybrid MBA as a typical lattice for a 4th generation storage ring are to adopt two large dispersion bumps in cell, and to make a -I-transformation between two dispersion bumps to cancel nonlinear effects. To increase the effectiveness of nonlinear control, analytical investigation of nonlinear phenomenon is essential. In this paper, we describe analytical investigation with a nonlinear driving term and simple model. We obtained similar results to the existing time-consuming MOGA optimization, but use a simplex optimizer with fewer nonlinear control knobs.

Multi-scale surface folding in metal cutting

In this work, commercially pure small-grained copper is used to investigate the nature of plastic flow through in situ image analysis supported by extensive electron backscatter diffraction characterization of the chip. Non-laminar sinuous flow, manifested with surface perturbations (bumps) and folds, produces a highly heterogeneous strain field during cutting. A series of mushroom-shaped morphology, termed as large bumps, separated by large folds on the free surface of the chip are captured in high-resolution field emission scanning electron microscopy. Large bumps or folds, captured in the high-speed camera, consist of many medium and small-size bumps. While the size of the small bump is comparable with the grain size of the base metal, a cluster of grains takes part in forming medium-size bumps. The pinning points for the small size bumps are either grain boundary or hard grains. The hard grains also act as pinning points for the medium size bump. The bump boundaries (folds) are characterized by higher strain and greater refinement of grains, whereas, less strain and larger elongated grains are the characteristics of the central region of the bumps. The evolution of different length scale features on the free surface is discussed in terms of the orientation of grain, position of the grains on the surface, and induced strain in the chip. This study suggested that the development of folding at different length scales is capable of providing deeper insight into the formation of a wide variety of chip morphology observed during the cutting of metals.

A Review on Automotive Heavy-Duty Chassis

The chassis frame is a significant part in a vehicle which it carries the entire load acting on the truck as well as different parts of the automobile. So, chassis must be robust enough to resist the shock, twist, vibration and other stresses. Therefore, the study of chassis under both static and dynamic load are crucial. The variable sections of chassis structure are shaped on the basis of varied loads acting along the length of the automotive to overcome the failure and preserve the safety. But the direct major or minor impacts on chassis frames in accidental cases may root the dynamic unbalancing, chassis misalignment and other problems which affect the vehicle performance as well as the appearance. Due to large and sudden bumps during running conditions may produce the vibrations inside the chassis which cause the prior failure in chassis members. This paper focus on the automotive heavy-duty 407 vehicle chassis under maximum load.

Contact feedback helps snake robots better use vertical bending to propel through uneven terrain.

Snakes can bend their elongate bodies in various forms to traverse various environments. We understand well how snakes use lateral body bending to push against asperities on flat ground for propulsion, and snake robots can do so effectively. However, snakes can also use vertical bending to push against uneven terrain of large height variation for propulsion, and they can adjust this bending to adapt to novel terrain presumably using mechano-sensing feedback control. Although some snake robots can traverse uneven terrain, few have used vertical bending for propulsion, and how to control this process in novel environments is poorly understood. Here we systematically studied a snake robot with force sensors pushing against large bumps using vertical bending to understand the role of sensory feedback control. We compared a feedforward controller and four feedback controllers that use different sensory information and generate distinct bending patterns and body-terrain interaction. We challenged the robot with increasing backward load and novel terrain geometry that break its contact with the terrain. We further varied how much the feedback control modulated body bending to conform to or push against the terrain to test their effects. Feedforward propagation of vertical bending generated large propulsion when the bending shape matched terrain geometry. However, when perturbations caused loss of contact, the robot easily lost propulsion or had motor overload. Contact feedback control resolved these issues by helping the robot regain contact. Yet excessive conformation interrupted shape propagation and excessive pushing stalled motors frequently. Unlike that using lateral bending, for propulsion generation using vertical bending, body weight that can help maintain contact with the environment but may also overload motors. Our results will help snake robots better traverse uneven terrain with large height variation and can inform how snakes use sensory feedback to control vertical body bending for propulsion.

Control for Hybrid Bumpless Transfer Performance of Discrete-Time Switched Systems With Event-Triggering

This paper addresses the dynamic event-triggered l2-l∞ bumpless transfer control for discrete-time switched systems without stable subsystems. A unified framework of bumpless transfer performance for discrete-time switched systems called hybrid bumpless transfer performance is established to rule out sudden large hybrid bumps induced by both triggering and switching. By constructing the multiple Lyapunov functions, sufficient conditions for the considered switched systems to be asymptotically stable with both l2-l∞ performance and hybrid bumpless transfer performance are obtained. Then, the state-dependent switching law and the dynamic event-triggered hybrid bumpless transfer controllers are jointly designed. Finally, the PWM-driven boost converter system is provided to verify the validity and applicability of our method.

Trauma Never Occurs Only Once: Being Traumatized by a Slap is Like Making Meaning of the Game of Peek-a-Boo

ABSTRACT It is argued that the lack of a normal developmental perspective along with a dominant psychopathological perspective framing our thinking about trauma limits our understanding of trauma, the value of trauma theory, and trauma informed practices. A developmental perspective sees dysfunction emerging from chronic repeated experiences and processes, primarily external interpersonal relational experiences and internal somatic and brain – neurosomatic processes. Repetition of trauma occurs because of the individual’s on-going endogenous reiterated neurosomatic meaning making processes of the meaning made of a recurrent or singular event given the flow of the context in which it occurs. Thus trauma, for me, is like a bulge in a landscape that we note in our language and diagnoses as if it was the only feature of the landscape, but typical trauma is in fact just a more severe outcropping on many small and large bumps making up a desolate toxic landscape. And while becoming traumatized is hardly a game, the process of making meaning of it and of a game, such as peek-a-boo is pretty much the same. At the heart of the similarity is the repetition of endogenous meaning making processes which most often, but not always because there are single occurrence events, travel with the event’s exogenous re-occurrence. The repetition instantiates the trauma and the game into the individual’s way of experiencing and being in the world. Thus, what makes sense for us as a guide for therapy – for children and adults – is to take our cue from the development of meaning: Approach therapeutic change like learning peek-a-boo. Do it often, do it in multiple ways that fully engage every level of the individual, and let the individual agenically control the process.

Urticaria in Nurses in the COVID-19 Ward: A Case Report

Introduction: Chlorhexidine is widely used in health centers as an antiseptic and disinfectant. Several cases of immediate and delayed hypersensitivity to chlorhexidine have been reported.
 Case report: We reported a case of a 26-year-old nurse working in Hospital X that came with a complaint of itch in several areas of the body that started four days before presenting at the hospital. The itch was continuously felt, and it started to form multiple large red bumps. Redness accompanied by dry skin was present between the fingers and palms. Cetirizine and dexamethasone did not relieve the symptoms. The patient has been working for six years in the inpatient unit and six months in the COVID-19 ward. Since the pandemic, she had been using alcohol-based hand rubs more frequently. The hospital uses chlorhexidine as an alcohol-based hand rub, which may cause hypersensitivity reactions to exposed health workers. The patient was finally diagnosed with acute urticaria. Based on the seven steps of occupational diagnosis of disease, it was still inconclusive whether the urticaria is an occupational disease because there was no data regarding the causal relationship between chlorhexidine exposure and the incidence of urticaria.
 Conclusion: Hence, it is necessary to carry out further diagnostic test with a puncture test. The hospital is still required to implement control measures toward chlorhexidine exposure.

Review of an Improved Longwall Panel Layout for Ground Control in Longwall Mining

Conventional longwall layout (CLL) for mining coal, trona, etc. is still fraught with problems including low resource recovery, wavy ground surface subsidence, bumps or rockbursts, gateroad support and maintenance, poisonous air hazard, spontaneous combustion in coal mines, instability of equipment at inclined, or steeply inclined working face, etc. In order to improve longwall mining, a novel alternate longwall panel layout that has been employed for over 20 years in China, Australia, and Russia, etc. is proposed termed “split-level longwall layout” (SLL). Gateroads on either end of the same SLL panel are split level, i.e., placed in different levels. This paper provides a review of existing research literature and insights on the problems encountered in CLL and the improvement of the new approach. Theoretical, numerical analysis, and field observation results of the new strategy demonstrate that the problems mentioned above in CLL are mitigated, and the development entries using the improved longwall system have a better stress environment with associated reduction in large roadway convergence, coal bumps or outbursts, and many other issues on ground control. Based on the current development of SLL and the future requirement of mining industry, the prospects as well as its applications, limitations, and concerns for SLL are presented.

Structure and reduction of large bumps formed on 4H-SiC epitaxial film originated from dislocations in substrate

Homo-epitaxial 4H-SiC films were grown by adding HCl gas with a high Cl/Si ratio and a low Si /H2 ratio in CVD process. A large number of large bumps originated from dislocations in bare substrate were observed for the film grown at Cl/Si ratio of 30 and at C/Si ratio of 1.05. Raman spectroscopy analysis and wet etching treatment for the film by mixed acid which consists of hydrofluoric acid (HF) and nitric acid (HNO3) revealed that the large bumps are Si islands. From the dependence of surface morphology of the films on C/Si ratio and Cl/Si ratio, it was found that the formation of Si islands is suppressed by decreasing C/Si ratio, even though large pits are formed by increasing Cl/Si ratio. From the results obtained in this study, formation mechanism of the Si island, originated from dislocations in the substrate, was also proposed.

Understanding electrokinetic thermodynamics in nanochannels

• Both the analytical and numerical conversion efficiency are obtained. • A maximum efficiency is found when the pore radius is around the Debye length. • Small roughness can improve the conversion efficiency. Understanding the electrokinetic conversion efficiency in a nanochannel is vital for designing energy storage and conversion devices. In this paper, an analytical electrokinetic energy conversion efficiency in a nanochannel is obtained based on the linear electrokinetic response. The analytical result shows that the conversion efficiency has a maximum with the increasing of the nanochannel pore radius. Numerical solutions based on the Poisson-Nernst-Planck (PNP) and Navier-Stokes (NS) equations are used to confirm the analytical expressions. Besides, the influences of the pore radius and surface roughness on the conversion efficiency in nanochannels are also studied by the numerical calculations. In particular, the influences of the surface roughness on the fluid flow, streaming current and streaming potential are examined. The results show that the large bumps and grooves representing the roughness can hinder the fluid flows and ion transports in the nanochannels. The maximum efficiency in a smooth nanochannel is higher than that in a rough channel. However, the small bumps and grooves can increase the surface area of the channel, which is beneficial to improving the conversion efficiency in some cases. This research can provide theoretical guidance to design electrokinetic energy conversion devices.

Optimizing X-Ray Inspection for Advanced Packaging Applications

ABSTRACT Over the coming decade, advanced packaging will become increasingly critical to performance, cost, and density improvements in advanced electronics. There is both an industry push: cost and performance advances in transistor scaling are increasingly difficult. And there is an industry pull: customization for each market can be done far more quickly by assembling a series of parts in a package, rather than by design and integration into a single device. This isnt a new idea: Gordon Moore said the same in the 60’s. But after decades of increased device level integration, it is an important change. Figure 1 shows an example (future) device: there are large bumps, hybrid bonds--for extreme bandwidth and low latency connection to cache memory, TSV based DRAM, and multiple CPU to CPU interconnects. Each of these is a failure point. Figure 1: The wide variety of interconnects on future advanced packages Figure 2: the triangle of misery as applied to standard and Advanced xray imaging (AXI) Manufacturing will necessarily advance in the packaging arena: pin density and package size will both increase to support the high bandwidth and device integration demands. The downside of multiple device integration is a higher set of requirements on the reliability of both the individual devices and the fully assembled system. This is an opportunity to take advantage of new strategies and technologies in package inspection. The sampling challenges for both control and inspection for high reliability require systems that can run at 100% coverage and millions of units per year. An overview of reliability sampling challenges as it relates to the end of line inspection, as well as sampling for both defect type and incidence is critical to understanding how and what to measure to maximize yield. There are fundamental tradeoffs between speed, resolution, and signal to noise ratio that inform a systematic engineering understanding of inspection. Optimizing that trade-off specifically for semiconductor inspection leads to dedicated tools with extremely high resolution, speed, and low dose. In parallel with the speed requirements, sensitivity, and noise immunity can be improved with an understanding of the systematic sources of noise. These can be mitigated and even eliminated with novel algorithms for both image enhancement and defect location.

Electron transport properties of graphene nanoribbons with Gaussian deformation

Gaussian deformation in graphene structures exhibits an interesting effect in which flower-shaped confinement states are observed in the deformed region [Carrillo-Bastos et al., Phys. Rev. B 90 041411 (2014)]. To exploit such a deformation for various applications, tunable electronic features including a bandgap opening for semi-metallic structures are expected. Besides, the effects of disorders and external excitations also need to be considered. In this work, we present a systematic study on quantum transport of graphene ribbons with Gaussian deformation. Different levels of deformation are explored to find a universal behavior of the electron transmission. Using a tight-binding model in combination with Non-Equilibrium Green Functions formalism, we show that Gaussian deformation influences strongly the electronic properties of ribbons in which the electron transmission decreases remarkably in high energy regions even if small deformations are considered. Interestingly, it unveils that the first plateau of the transmission of semi-metallic armchair ribbons is just weakly affected in the case of small deformations. However, significant large Gaussian bumps can induce a strong drop of this plateau and a transport gap is formed. The transmission at the zero energy is found to decrease exponentially with increasing the size of the Gaussian bump. Moreover, the gap of semi-conducting ribbons is enlarged with large deformations. The opening or the widening of the transport gap in large deformed armchair structures is interpreted by a formation of a three-zone behavior along the transport direction of the hopping profile. On the other hand, a transport gap is not observed in zigzag ribbons regardless of the size of Gaussian bumps. This behavior is due to the strong localization of edge states at the energy point E = 0...

Origin of Large Bumps Abnormally Grown on 4H-SiC Epitaxial Film by Adding HCl Gas with High Cl/Si Ratio in CVD Process

4H-SiC homo-epitaxial film was grown by adding HCl gas with a high Cl/Si ratio in CVD process, and defect formation and origin of the defect were investigated by confocal differential interference contrast (CDIC) microscope, PL imaging and normal differential interference contrast (DIC) microscope. It was found that a large number of large bumps are formed on the film grown at a high Cl/Si ratio of 30, and a large number of PL defects on bare substrate before the film growth are also observed. Coordinates where the bumps on the film are observed were good agreement with those where the PL defects on the bare substrate are observed. An etch pit sample on reproduced substrate from which epitaxial film was removed was fabricated by etching process using molten KOH+Na2O2, and some types of etch pits which might be originated from threading edge dislocations (TEDs), threading screw dislocations (TSDs) and basal plane dislocations (BPDs) in the substrate were observed. The coordinates where the etch pits on the reproduced substrate are observed were also good agreement with those where the bumps on the epitaxial film are observed. Therefore, it was clarified that a large number of the bumps abnormally grown on the epitaxial film are originated from the dislocations in the substrate.

Features and prospects of using ekranoplanes in the Arctic

The article is devoted to the problem of year-round transport service of the Arctic territories and settlements, necessary for their sustainable economic and social development, for the functioning of the units of the Ministry of defense. It is shown that the solution of this problem can contribute to the revival of construction in Russia of large Wing- in- Ground craft (WIG-craft) of the new generation, the first of which «Orlan», as stated by the heads of the relevant Russian agencies, is planned to be built before 2027. Its application can be multifunctional. The features of the organization of takeoff, cruising flight mode and landing on ice, snow or water are discussed. The advantages of using ekranoplane in the Arctic in comparison with other vehicles are estimated. The problem of ensuring safe and effective flight near the surface with ice hummocks, the problem of rough alignment of such a surface in a narrow corridor allocated for takeoff and landing of ekranoplanes is discussed. In contrast to the airfields for planes, this “strip” may be acceptable for a large airplane bumps up to half a meter tall. A special technique may be required for rough smoothing of hummocks with minimal energy consumption. Previously Arctic conditions of flight of WIG-craft were not considered. The main idea of the article: in the Arctic, in some cases, it is better to use an ekranoplane to fly over the ice, than to break the ice with an icebreaker for the wiring of ships or to build a highway for the movement of cars.

Pneumohydraulic spring with adaptive self-adjusting damper for suspension of a high-speed tracked vehicle and its calculation procedure

Currently, a further increase in the mobility of high-speed vehicles is largely limited by the existing suspension systems, which mainly have unregulated characteristics, and the developed adjustable suspension systems with external control are very complex, expensive and less reliable. Therefore, the development of relatively simple and reliable self-adjusting suspensions for high-speed machinery is an urgent task. At the Department of Automatic Installations of Volgograd State Technical University an original design of an air-hydraulic spring (AHS) with an adaptive self-regulating damper for suspension of a high-speed tracked vehicle (HSTV) was developed. A feature of its adaptive damper is the provision of a two-stage inelastic resistance depending on the amplitude, frequency and direction of oscillation, which can significantly reduce the acceleration of the «shaking» and heating of AHS when the HSTV moves along small irregularities, as well as practically eliminate suspension breakdowns when large vertical and angular vibrations occur at the vehicles body when driving on large bumps or springboards with a takeoff of the rollers from the supporting surface. These modes of operation are ensured by installing two spring-loaded step plungers in the serial AHS body, which in a static position and with small spring lift open an additional throttle channel, which significantly reduces the inelastic resistance of the suspension, and at large strokes they block this channel, thereby significantly increasing damping fluctuations. Due to the fact that these plungers are equipped with a system for delaying their movement in the opposite direction, the increased resistance is maintained for several periods of oscillation. The article also presents an engineering methodology and a numerical example of determining the parameters of the main elements of an adaptive self-regulating damper, the elastic and damping characteristics of the AHS taking into account the operation of the pressure relief valve and the rebound check valve.

Electrophysiological adaptations of insect photoreceptors and their elementary responses to diurnal and nocturnal lifestyles

Nocturnal vision in insects depends on the ability to reliably detect scarce photons. Nocturnal insects tend to have intrinsically more sensitive and larger rhabdomeres than diurnal species. However, large rhabdomeres have relatively high membrane capacitance (Cm), which can strongly low-pass filter the voltage bumps, widening and attenuating them. To investigate the evolution of photoreceptor signaling under near dark, we recorded elementary current and voltage responses from a number of species in six insect orders. We found that the gain of phototransduction increased with Cm, so that nocturnal species had relatively large and prolonged current bumps. Consequently, although the voltage bump amplitude correlated negatively with Cm, the strength of the total voltage signal increased. Importantly, the background voltage noise decreased strongly with increasing Cm, yielding a notable increase in signal-to-noise ratio for voltage bumps. A similar decrease in the background noise with increasing Cm was found in intracellular recordings in vivo. Morphological measurements of rhabdomeres were consistent with our Cm estimates. Our results indicate that the increased photoreceptor Cm in nocturnal insects is a major sensitivity-boosting and noise-suppressing adaptation. However, by requiring a compensatory increase in the gain of phototransduction, this adaptation comes at the expense of the signaling bandwidth.

Radiation hard active pixel sensor with [formula omitted][formula omitted][formula omitted] pixel size designed for capacitive readout with RD53 ASIC

A new concept for a capacitively coupled particle detector (CCPD) is described. Sensor and readout chips are attached using a small number of large bumps. A sensor chip for such a CCPD has been designed and tested. The sensor chip is based on the HVCMOS structure. Deep n-well is used as the charge collecting electrode. To allow strong amplification, which is necessary for chip to chip signal transmission, a novel CMOS based comparator with rail to rail output swing has been implemented in each pixel. The pixel outputs are connected to transmitting electrodes implemented in the top metal layer of the sensor chip. Using special address encoding a group of 16 pixels is connected to 8 transmitting electrodes. The pixel size is 25μm×50μm and the transmitting electrode pitch is 50μm×50μm. Therefore a standard HL-LHC readout chip developed by RD53 collaboration can be used for readout of the sensor.

Surface Morphologies in Ultra-short Pulsed Laser Processing of Stainless-Steel at High Repetition Rate

Stainless-steel is ablated with femtosecond laser pulses at high repetition rate. A multi-pass, high spatial overlap laser scanning strategy is applied in order to cope with the requirements for large-scale machining of high aspect ratio structures. Topography of the processed surfaces is analyzed via Shear Force Microscopy scans, with the main aim to investigate morphology changes as a function of process parameters. Quantitative assessment of local height variations enables a detailed investigation of the produced features. Depending on the process parameters, in particular on laser fluence and repetition rate, a transition from small islands to large bumps is observed, explained in terms of feature coalescence.