Prediction of Coefficient of Restitution for Impact Elastoplastic Spheres Considering Finite Plate Thickness

Collisions between objects are a relatively common phenomenon in nature.Analyses of collision processes can greatly contribute to solving problems such as impact-rub faults and particle impacts.The coefficient of restitution is a critical parameter in the analysis of collision processes.Many experiments have shown that the coefficient of restitution is closely related to the plate thickness,and the smaller the plate thickness,the more inaccurate the coefficient of restitution predicted by the existing model,which seriously affects the process of collision analysis.To remedy this shortcoming,this paper proposes a plate thickness influence factor with the ratio of sphere diameter to plate thickness as the variable.The plate thickness influence factor can optimize the coefficient of restitution model to effectively predict the coefficient of restitution of impacting elastoplastic spheres with finite plate thickness.Finally,the validity of the new model is verified using a large amount of experimental data.

A Proposal for the Restitution of the World’s First Baptistry and University, Mor Yakup Church, Turkey

The structure known today as St.Jacob’s Church represents one of the oldest Christian medieval monuments in the region.With the emergence of findings suggesting that the structure was the world’s first university during recent excavation efforts,it has gained even more significance.Since 2006,the excavation works conducted by the Mardin Museum Directorate in the vicinity of Mor Yakup Church have yielded information about various phases of the structure.However,assessments regarding the nature of the structure are still debated within the academic environment.This study aimed to thoroughly investigate the functional changes and periods that St.Jacob’s Church underwent throughout history and to provide a detailed description and restitution for each period.In this study,we utilized excavation reports,data from written sources related to the settlement and structure,information obtained from the structure itself,traces existing on the structure,and data derived from architectural necessities(logic/scenario).The results indicate that this structure served three different functions(baptistry,church,university)and went through two main periods(pre-Christianity and post-Christianity).

Functional and morphological changes of the gut barrier during the restitution process after hemorrhagic shock

AIM： To investigate the functional, morphological changes of the gut barrier during the restitution process after hemorrhagic shock, and the regional differences of the large intestine and small intestine in response to ischemia/ reperfusion injury. METHODS： Forty-seven Sprague-Dawley rats with body weight of 250-300 g were divided into two groups： control group （sham shock n = 5） and experimental group （n = 42）. Experimental group was further divided into six groups （n = 7 each） according to different time points after the hemorrhagic shock, including 0^th group, 1^st group, 3^rd group, 6th h group, 12^th group and 24^th group. All the rats were gavaged with 2 mL of suspension of lactulose （L） （100 mg/2 mL） and mannitol （M） （50 mg/each） at the beginning and then an experimental rat model of hemorrhagic shock was set up. The specimens from jejunum, ileum and colon tissues and the blood samples from the portal vein were taken at 0, 1, 3, 6, 12 and 24 h after shock resuscitation, respectively. The morphological changes of the intestinal mucosa, including the histology of intestinal mucosa, the thickness of mucosa, the height of villi, the index of mucosal damage and the numbers of goblet cells, were determined by light microscope and/or electron microscope. The concentrations of the bacterial endotoxin lipopolysaccharides （LPS） from the portal vein blood, which reflected the gut barrier function, were examined by using Limulus test. At the same time point, to evaluate intestinal permeability, all urine was collected and the concentrations of the metabolically inactive markers such as L and M in urine were measured by using GC-9A gas chromatographic instrument.RESULTS： After the hemorrhagic shock, the mucosal epithelial injury was obvious in small intestine even at the 0th h, and it became more serious at the 1^stand the 3^rd h. The tissue restitution was also found after 3 h, though the injury was still serious. Most of the injured mucosal restitution was established after 6 h and completed in 24 h. Two distinct models of cell deathapoptosis and necrosis-were involved in the destruction of rat intestinal epithelial cells. The number of goblet cells on intestinal mucosa was reduced significantly from 0 to 24 h （the number from 243±13 to 157±9 for ileum, 310±19 to 248±18 for colon; r= -0.910 and -0.437 respectively, all P〈0.001）, which was the same with the large intestine, but the grade of injury was lighter with the values of mucosal damage index in 3 h for jejunum, ileum, and colon being 2.8, 2.6, 1.2, respectively. The mucosal thickness and the height of villi in jejunum and ileum diminished in 1 h （the average height decreased from 309±24 to 204±23 pm and 271±31 to 231±28 pm, r = -0.758 and -0.659, all P〈0.001, the thickness from 547±23 to 418±28μm and 483±45 to 364±35μm, r= -0.898 and -0.829, all P〈0.001）, but there was no statistical difference in the colon （F= 0.296, P = 0.934）. Compared with control group, the urine L/M ratio and the blood LPS concentration in the experimental groups raised significantly, reaching the peak in 3-6 h （L/M： control vs 3 h vs6 h was 0.029±0.09 vs 0.063±0.012 vs 0.078±0.021, r = -0.786, P〈0.001; LPS： control vs3 h vs6 h was 0.09±0.021 vs 0.063±0.012 vs0.25±0.023, r=- -0.623, P〈0.001）, and it kept increasing in 24 h. CONCLUSION： The gut barrier of the rats was seriously damaged at the early phase of ischemic reperfusion injury after hemorrhagic shock, which included the injury and atrophy in intestinal mucosa and the increasing of intestinal permeability. Simultaneously, the intestinal mucosa also showed its great repairing potentiality, such as the improvement of the intestinal permeability and the recovery of the morphology at different phases after ischemic reperfusion injury. The restitution of gut barrier function was obviously slower than that of the morphology and there was no direct correlation between them. Compared with the small intestine, the large intestine had stronger potentiality against injury. The reduction of the amount of intestinal goblet cells by injury did not influence the ability of intestinal mucosal restitution at a certain extent and it appeared to be intimately involved in the restitution of the epithelium.

Production of aneuhaploid and euhaploid sporocytes by meiotic restitution in fertile hybrids between durum wheat Langdon chromosome substitution lines and Aegilops tauschii

Fertile F1 hybrids were obtained between durum wheat （Triticum durum Desf.） Langdon （LDN） and its 10 disomic substitution （LDN DS） lines with Aegilops tauschii accession AS60 without embryo rescue. Selfed seedset rates for hybrids of LDN with AS60 were 36.87% and 49.45% in 2005 and 2006, respectively. Similar or higher selfed seedset rates were observed in the hybrids of 1D （1A）, 1D （1B）, 3D （3A）, 4D （4B）, 7D （7A）, and 2D （2B） with AS60, while lower in hybrids of 3D （3B） ＋ 3BL, 5D （5A） ＋ 5AL, 5D （5B） ＋ 5B and 6D （6B） ＋ 6BS with AS60 compared with the hybrids of LDN with AS60. Observation of male gametogenesis showed that meiotic restitution, both first-division restitution （FDR） and single-division meiosis （SDM） resulted in the formation of functional unreduced gametes, which in turn produced seeds. Both euhaploid and aneuhaploid gametes were produced in F1 hybrids. This suggested a strategy to simultaneously transfer and locate major genes from the ancestral species T. turgidum or Ae. tauschii. Moreover, there was no significant difference in the aneuhaploid rates between the F1 hybrids of LDN and LDN DS lines with AS60, suggesting that meiotic pairing between the two D chromosomes in the hybrids of LDN DS lines with AS60 did not promote the formation of aneuhaploid gametes.

Transformations of phosphatidylinositol phosphates in the outer and inner nuclear membrane are linked to synthesis and restitution of cellular membranes

The ultimate goal in phosphoinositides cellular metabolism is to decipher their global functional organization and coordination of the com- partmentalized signaling processes. In this report we present evidence linking nuclear phos- phoinositides cycle with endoplasmic reticulum synthesis and function. The rapid transformation of [3H]inositol-labeled phosphoinositides in the intact nuclei (IN) was captured in chase studies for 0-5 min, followed by examination of phosphatidylinositides in the inner nuclear me- mbrane (INM), the outer nuclear membrane (ONM) and endoplasmic reticulum (ER). We revealed that synthesis of phosphatidylinositol phosphates (PIPs) occurs in ONM and the de- phosphorylation takes place in the INM. The rapid transformation of the radiolabeled PIPs in ONM reverberated in their appearance and successive transformation in INM, and in the 5min chased nuclei was tracked to ONM as the re- emerging radiolabeled phosphatidylinositol (PI). These chase-uncovered changes in ONM and INM PIPs profiles allow us to conclude that the observed conversions in the nuclear membrane continuum are induced by the lateral movement of the membrane and its transit from the cytosolic to nuclear and back to cytosolic environment. The suggested membrane synthesisinduced movement provides the means to transport the membrane- and the membrane lipid ligand-associated cytosolic proteins to the intranuclear spaces and renewal of INM. Export of the nuclear components interacting with the modified INM, by exiting from nuclear to cytosolic site, endows ER with a steady influx of the membrane that is conditioned to generate vesicles according to the nucleus delivered templates.

Determination of action potential wavelength restitution in Scn5a^＋/- mouse hearts modelling human Brugada syndrome

Brugada syndrome is a primary electrical disorder of theheart, predisposing affected individuals to potentially lethal,ventricular tachy-arrhythmias. A number of mechanismshave been identified as being important increasing the riskof these rhythms. Wavelength （γ） restitution has beensuggested to predict the onset of action potential duration（APD） alternans in mouse Scn5a^＋/- hearts modelling Bru-gada syndrome.

Modeling of softsphere normal collisions with characteristic of coefficient of restitution dependent on impact velocity

This letter presents a theoretical model of the normal （head-on） collisions between two soft spheres for predicting the experimental characteristic of the coefficient of restitution dependent on impact velocity. After the contact force law between the contacted spheres during a collision is phenomenologically formulated in terms of the compression or overlap displacement under considera- tion of an elastic-plastic loading and a plastic unloading subprocesses, the coefficient of restitution is gained by the dynamic equation of the contact process once an initial impact velocity is input. It is found that the theoretical predictions of the coefficient of restitution varying with the impact velocity are well in agreement with the existing experimental characteristics which are fitted by the explicit formula.

Concluding Step in Cell Restitution Cycle: ER Transport Vesicles with Sphingolipids in the Outer Leaflet of the Membrane Restore Lysosomes

Restitution of the cell organelles and the membrane implicates serine palmitoyltransferase (SPT) in signal-specific and selective assembly of the transport vesicles. Here, we reveal that SPT, embedded in the outer leaflet (OL) of endoplasmic reticulum (ER), is engaged in the synthesis of ER transport vesicles that recondition cell organelles, and the inner leaflet (IL) SPT in the restitution of the cell membrane. The OL SPT impacts assembly of sphingomyelinase (SMase)—susceptible ER vesicles but not the SMase-resistant and sphingolipid (SPhL) core—carrying vesicles that refurbish the cell membrane. The investigation of the SPT-initiated differences in the placement of SPhL in vesicular membranes by utilizing ER depleted of OL SPT, allows us to conclude that the restitution of endosomal and lysosomal membranes is achieved with the involvement of OL SPT, whereas the IL SPT is involved in formation of the lipid core for glycosphingolipids (GSL) and sphingomyelin (SM) of the apical and basolateral cell membrane. These findings along with our previously published report (Slomiany and Slomiany, Advances in Biological Chemistry, 2013, 3, 275-287), provide a clear distinction between the processes that renovate cell membrane and its organelles from that of the endocytotic cell debridement, and show that vesicles are navigated to the specific organelles and the cell membrane by the biomembrane constituents programmed in ER.

The Graphical Method for Decision of Restitution Coefficient and Its Applications

In this paper we present a graphical method for decision of restitution coefficient based on ODE. To simulate and illustrate our proposed method and efficient characteristics that demonstrate for two colliding bodies we used MatLab. In simulation to approach to the real case we used an assumption of additional virtual body’s position and velocity for characterizing material of the body which is involved to express the restitution coefficient. The graphic animation program is developed based on ODE for the computer simulation of the proposed graphical method. Additionally, we determined this new characteristic for some sport game balls such as basketball, volleyball, etc.

CFD Simulation of Particles Mixing and Segregation in a Rotary Coating Disk: Influence of Drag Models and Restitution Coefficient

In this paper, the dynamics of a transverse plane of a rotary coating disk of a binary mixture system comprising sand and urea particles were simulated using the two-fluid model along with the kinetic theory of granular flow in Fluent 19.1. Although some parameters relating to the material properties and size of the rotary coating disk have been researched, the effects of both drag force and restitution coefficient on the flow characteristics have yet to be examined. Thus, this paper numerically examines the effect of the inclusion of drag models and particle-particle restitution coefficients on particle dynamics in a rotary disk operating in the rolling regime of the granular bed. Three particle-particle drag models were considered: the Schiller-Naumann, Syamlal-O’Brien, and Gidaspow. The Syamlal-O’Brien and Gidaspow models were both able to successfully simulate particle segregation in a perfect rolling regime, whereas the Schiller-Naumann drag model appeared to be unable to predict the segregation of the particles and the rolling flow regime under the assumed conditions. Four different values of the restitution coefficient were also investigated: 0.7, 0.8, 0.9, and 0.95. The higher restitution values of 0.9 and 0.95 were found to substantially affect flow characteristics, ensuring suitable rolling regime behaviour for the bed during the rotational movement. The lower restitution coefficients of 0.7 and 0.8, on the other hand, indicated that irregular velocity vectors could be obtained in the active region of the granular bed.

Epithelial restitution and wound healing in inflammatory bowel disease

Inflammatory bowel disease is characterized by a chronic inflammation of the intestinal mucosa. The mucosal epithelium of the alimentary tract constitutes a key element of the mucosal barrier to a broad spectrum of deleterious substances present within the intestinal lumen including bacterial microorganisms, various dietary factors, gastrointestinal secretory products and drugs. In addition, this mucosal barrier can be disturbed in the course of various intestinal disorders including inflammatory bowel diseases. Fortunately, the integrity of the gastrointestinal surface epithelium is rapidly reestablished even after extensive destruction. Rapid resealing of the epithelial barrier following injuries is accomplished by a process termed epithelial restitution, followed by more delayed mechanisms of epithelial wound healing including increased epithelial cell proliferation and epithelial cell differentiation. Restitution of the intestinal surface epithelium is modulated by a range of highly divergent factors among them a broad spectrum of structurally distinct regulatory peptides, variously described as growth factors or cytokines. Several regulatory peptide factors act from the basolateral site of the epithelial surface and enhance epithelial cell restitution through TGF-13-dependent pathways. In contrast, members of the trefoil factor family （TFF peptides） appear to stimulate epithelial restitution in conjunction with mucin glycoproteins through a TGF-13-independent mechanism from the apical site of the intestinal epithelium. In addition, a number of other peptide molecules like extracellular matrix factors and blood clotting factors and also non- peptide molecules including phospholipids~ short-chain fatty acids （SCFA）, adenine nucleotides, trace elements and pharmacological agents modulate intestinal epithelial repair mechanisms. Repeated damage and injury of the intestinal surface are key features of various intestinal disorders including inflammatory bowel diseases and require constant repair of the epithelium. Enhancement of intestinal repair mechanisms by regulatory peptides or other modulatory factors may provide future approaches for the treatment of diseases that are characterized by injuries of the epithelial surface.

Wound healing of intestinal epithelial cells

The intestinal epithelial cells(IECs) form a selective permeability barrier separating luminal content from underlying tissues.Upon injury,the intestinal epithelium undergoes a wound healing process.Intestinal wound healing is dependent on the balance of three cellular events;restitution,proliferation,and differentiation of epithelial cells adjacent to the wounded area.Previous studies have shown that various regulatory peptides,including growth factors and cytokines,modulate intestinal epithelial wound healing.Recent studies have revealed that novel factors,which include toll-like receptors(TLRs),regulatory peptides,particular dietary factors,and some gastroprotective agents,also modulate intestinal epithelial wound repair.Among these factors,the activation of TLRs by commensal bacteria is suggested to play an essential role in the maintenance of gut homeostasis.Recent studies suggest that mutations and dysregulation of TLRs could be major contributing factors in the predisposition and perpetuation of inflammatory bowel disease.Additionally,studies have shown that specific signaling pathways are involved in IEC wound repair.In this review,we summarize the function of IECs,the process of intestinal epithelial wound healing,and the functions and mechanisms of the various factors that contribute to gut homeostasis and intestinal epithelial wound healing.

A theoretical model of collision between soft-spheres with Hertz elastic loading and nonlinear plastic unloading

This paper presents a theoretical model on the normal(head-on) collision between soft-spheres on the basis of elastic loading of the Hertz contact for compression process and a nonlinear plastic unloading for restitution one,in which the parameters all are determined in terms of the material and geometric ones of the spheres,and the behaviors of perfect elastic,inelastic,and perfect plastic collisions appeared in the classical mechanics are fully described once a value of coefficient of restitution is specified in the region of 0 ≤ ε ≤ 1.After an empirical formula of the coefficient of restitution dependent on the impact velocity is suggested to fit the existing experimental measurements by means of the least square method,the predictions of the dependency and the collision duration are in well quantitative agreement with their experimental measurements.It is found that the measurable quantities are dependent on both the impact velocity and the parameters of spheres.Following this model,finally,an approach to determine the spring coefficient in the linear viscoelastic model of the collision is also displayed.These results obtained here will be significantly beneficial for the applications where a collision model is requested in the simulations of relevant grain flows and impact dynamics etc..

Long-term effect of subacute ruminal acidosis on the morphology and function of rumen epithelial barrier in lactating goats

Grain-induced subacute ruminal acidosis(SARA)impairs rumen epithelial barrier function,but it is yet to be determined if SARA can cause persistent damage to the morphology and function of the rumen epithelial barrier.The objective of the present study was to investigate if SARA has persistent effects on the morphological structure and permeability of ruminal epithelium and the expression of the genes involved in epithelial barrier function using a lactating goat model.Twelve mid-lactating Saanen goats with rumen cannulas were randomly assigned to 1 of 2 groups:control group(Ctrl,n=4)fed a basal diet with a non-fiber carbohydrate(NFC)to neutral detergent fiber(NDF)ratio of 1.40,and SARA group(SARA,n=8)fed the same basal diet but with increasing NFC to NDF ratio from 1.4 to 1.79,2.31,and 3.23 overtime to induce SARA.At the end of the SARA challenge(post-SARA),4 goats were randomly selected from the SARA group and fed only hay mixture ad libitum for another 4 weeks to allow for restitution(post-SARA).Ruminal pH was continuously recorded to monitor the severity of SARA.Samples of the ventral ruminal epithelium were collected after slaughter to examine the structural and functional changes of the ruminal epithelium using transmission electron microscopy(TEM),Ussing chambers,qRT-PCR,and Western bolt analyses.Compared with the Ctrl group,ruminal papilla length,width,surface area and thickness of stratum corneum increased(P<0.05),while stratum spinosum and basale thickness,and total depth of the epithelium decreased(P<0.05)in the SARA group.These changes diminished or tended to return to the levels of the Ctrl group in the post-SARA group(P>0.05).The SARA challenge also decreased cellular junction and widened the intercellular space between epithelial cells.Rumen transepithelial short-circuit current(Isc),tissue conductance(Gt),and mucosa-to-serosa flux of paracellular horseradish peroxidase(HRP)all increased(P<0.05)both in the SARA and post-SARA groups,which indicates that SARA can induce a sustained increase in epithelial permeability and barrier dysfunction.Moreover,the mRNA and protein expressions of CLDN1,OCLN and ZO-1 were down-regulated(P<0.01)in both the SARA and post-SARA groups.The results of this study showed that SARA could result in sustained epithelial barrier dysfunction,at both structural and functional levels,which is associated with decreased expression of rumen epithelial tight junction proteins,and the restitution of rumen epithelial barrier function is slower than that of its morphology.

Analysis of force and energy density transferred to barrier in a single degree of freedom vibro-impact system

A mass-spring-damper linear oscillator with a limiting stop barrier is presented. Modeling non-smooth processes in mechanical engineering is a complex problem. It is especially for the systems with more than a single degree of freedom. But recent studies in dynamical systems have been applied to single degree of freedom systems. The vibrating system, consisting of an oscillator with amplitude of motion limited by a barrier, is known as a vibro-impact system. The amount of force and kinetic energy transferred to a barrier has an important application in designing of engineering systems that undergo the vibro-impact phenomenon. The results show the effect of changing restitution coefficient of a barrier on the amount of force and energy absorbed.

Investigation of Dynamic Behavior in 1D Non-uniform Granular System

We present a non-uniform granular system in one-dimensional case, whose granularity distribution has the fractal characteristic. The particles are subject to inelastic mutual collisions and obey Langevin equation between collisions. By Monte Carlo simulation we study the dynamic actions of the system. Far from the equilibrium, i.e., τ 〉〉 τe, the results of simulation indicate that the inhomogeneity of the system and the inelasticity of the particles have great influences on the dynamic properties of the system, and correspondingly the influence of the inhomogeneity is more significant.

RESTORATION OF THE IMAGE DEGRADED BY LINEAR MOTION

This paper introduces a new effective method to restore the uniform linear motion blurred im-age. The effect of the out-of-frame pixels on the blurring process and the estimate of these pixelsare analysed. The restoration qualities of different deblurring methods are compared. Finally, theauthors come to a conclusion that it is impossible to determine the length of blurring movement infrequency domain.

Mitochondrial Membranes Restitution Proceeds via Vesicular Import from ER and Cytosol. Counterparts’ Resemblances and Variances in Mitochondria and Golgi Pathways

The processes of mitochondrial restitution are controlled by nuclear genes that encode proteins synthesized in ER and cytosol and delivered as organelle- and membrane-specific transport vesicles. The analysis of the transporters recovered from inner mitochondrial space (Mitosol) revealed that the ER-synthesized mitochondria-specific transport vesicles consist of two carriers, one remaining in outer mitochondrial membrane (OMM), and the other that transfers specific membrane segments to the inner mitochondrial membrane (IMM). The ER-assembled and IMM-committed membrane segments, while first integrated into OMM, undergo intra-mitochondrial lipid modification reflected in the synthesis of cardiolipin (CL) and inversion into Mitosol with load of IMM associated cytosolic proteins. Then, the CL-bedecked vesicles are released from OMM to Mitosol and upon contact with IMM fuse with the membrane, and the release of cytosolic cargo ensues. While ER-assembled mitochondria-specific transport vesicles fuse with OMM with the aid of the cytosolic, phosphatidylglycerol (PG)-specific phospholipase A2 (PLA2), the Mitosol-contained CL-specific PLA guides vesicles fusion with IMM. The described path of translocation of the membrane segments and the cytosol synthesized proteins into the designated mitochondrial compartments sustains growth and identity of OMM, IMM, maintains protein delivery for intra-mitochondrial lipid and protein modification in Mitosol, and ensures conformity of the cytosolic proteins cargo delivered to matrix.

Equivalent Kelvin Impact Model for Seismic Pounding Analysis of Bridges

Based on Hertz contact theory, a method to determine the parameters of Kelvin impact model for seismic pounding analysis of bridges is proposed. The impact stiffness of Kelvin model is determined by the ratio of maximum impact force to maximum contact deformation, which is calculated based on Hertz contact theory with considering the vibration effect. The restitution coefficient which has great influence on the damping coefficient of Kelvin impact model is investigated by numerical analysis. Numerical results indicate that the impact stiffness of Kelvin impact model increases with the increment of the Hertz contact stiffness, approaching velocity or the length ratio of short to long girders. Vibration effect has remarkable influence on the impact stiffness and cannot be neglected. The restitution coefficient decreases when approaching velocity increases or the length ratio of short girder to long girder decreasing. The practical ranges of impact stiffness and restitution coefficient are obtained as 3 × 10^8--6 × 10^8 N/m and 0.6-3.95 respectively.

Global Pressure of One-Dimensional Polydisperse Granular Gases Driven by Gaussian White Noise

We study the global pressure of a one-dimensional polydisperse granular gases system for the first time, in which the size distribution of particles has the fractal characteristic and the inhomogeneity is described by a fractal dimension D. The particles are driven by Gaussian white noise and subject to inelastic mutual collisions. We define the global pressure P of the system as the impulse transferred across a surface in a unit of time, which has two contributions, one from the translational motion of particles and the other from the collisions. Explicit expression for the global pressure in the steady state is derived. By molecular dynamics simulations, we investigate how the inelasticity of collisions and the inhomogeneity of the particles influence the global pressure. The simulation results indicate that the restitution coefficient e and the fractal dimension D have significant effect on the pressure.