Mechanical microenvironments of living cells: a critical frontier in mechanobiology

The fields of biomechanics and mechanobiology have long been predicated on the premise that mechanics governs cell behavior. However, over the past few years, a growing body of evidence has suggested that the mechanical environment very close to cells–the cell microenvironment–plays the most important role in determining what a cell feels and how it responds to tissue-level stimuli. To complicate matters further, cells can actively manipulate their microenvironments through pathways of recursive mechanobiological feedback. Harnessing this recursive behavior to understand and control cell physiology and pathophysiology is a critical frontier in the field of mechanobiology. Recent results suggest that the key to opening this scientific frontier to investigation and engineering application is understanding a different frontier: the physical frontier that cells face when probing their mechanical microenvironments.

Synergic effect of covalent and chemical sulfur fixation enhancing the immobilization-conversion of polysulfides in lithium-sulfur batteries

Lithium-sulfur batteries(LSBs)are promising as the next generation energy storage options.However,their wide applications have been technically challenged by the diffusion losses of polysulfides and polysulfide shuttle effect.In this work,the small organic molecules of 2,5-dichloropyrazine(2,5-DCP)were combined with Co-doped carbon(CoA NAC)flakes to achieve the synergic effect of the covalent and chemical sulfur fixation,so as that the immobilization-conversion of polysulfides in LSBs was greatly enhanced.More specifically,the nucleophilic substitution of the 2,5-DCP additive in the electrolyte with polysulfides formed the CAS bonds.Through the further covalent N-Li bonds between the N atoms in 2,5-DCP and polysulfides,sulfur fixation was achieved in the form of solid organosulfur.Meanwhile,the CoA NAC flakes served as the sulfur cathode to chemically anchor the polysulfides.The interaction mechanism between CoA NAC/2,5-DCP and polysulfides was explored by the density functional theory(DFT)calculations and in-situ infrared spectroscopy.The results showed that the optimal“with 2,5-DCP”sample-assembled LSB exhibited an initial discharge specific capacity of 1244 mA h g^(-1)at 0.2C,and a capacity decay rate of 0.053%per cycle was displayed after 800 cycles at 1C.The good cycling stability with a high sulfur-loaded electrode sample suggested that the synergic effect of covalent/chemical sulfur fixation enabled the enhancement of polysulfides immobilization-conversion in LSBs.

Application-oriented hydrolysis reaction system of solid-state hydrogen storage materials for high energy density target:A review

Hydrogen storage and delivery technology is still a bottleneck in the hydrogen industry chain.Among all kinds of hydrogen storage methods,light-weight solid-state hydrogen storage(LSHS)materials could become promising due to its intrinsic high hydrogen capacity.Hydrolysis reaction of LSHS materials occurs at moderate conditions,indicating the potential for portable applications.At present,most of review work focuses on the improvement of material performance,especially the catalysts design.This part is important,but the others,such as operation modes,are also vital to to make full use of material potential in the practical applications.Different operation modes of hydrolysis reaction have an impact on hydrogen capacity to various degrees.For example,hydrolysis in solution would decrease the hydrogen capacity of hydrogen generator to a low value due to the excessive water participating in the reaction.Therefore,application-oriented operation modes could become a key problem for hydrolysis reaction of LSHS materials.In this paper,the operation modes of hydrolysis reaction and their practical applications are mainly reviewed.The implements of each operation mode are discussed and compared in detail to determine the suitable one for practical applications with the requirement of high energy density.The current challenges and future directions are also discussed.

Continuous Fabrication of Ti_(3)C_(2)T_x MXene-Based Braided Coaxial Zinc-Ion Hybrid Supercapacitors with Improved Performance

Zinc-ion hybrid fiber supercapacitors(FSCs)are promising energy storages for wearable electronics owing to their high energy density,good flexibility,and weavability.However,it is still a critical challenge to optimize the structure of the designed FSC to improve energy density and realize the continuous fabrication of super-long FSCs.Herein,we propose a braided coaxial zinc-ion hybrid FSC with several meters of Ti_(3)C_(2)T_x MXene cathode as core electrodes,and shell zinc fiber anode was braided on the surface of the Ti_(3)C_(2)T_x MXene fibers across the solid electrolytes.According to the simulated results using ANSYS Maxwell software,the braided structures revealed a higher capacitance compared to the spring-like structures.The resulting FSCs exhibited a high areal capacitance of 214 mF cm^(-2),the energy density of 42.8μWh cm^(-2)at 5 mV s^(-1),and excellent cycling stability with 83.58%capacity retention after 5000 cycles.The coaxial FSC was tied several kinds of knots,proving a shape-controllable fiber energy storage.Furthermore,the knitted FSC showed superior stability and weavability,which can be woven into watch belts or embedded into textiles to power smart watches and LED arrays for a few days.

Influence of processing route on microstructure and wear resistance of fly ash reinforced AZ31 magnesium matrix composites

Utilizing fly ash(FA)as reinforcement for magnesium matrix composites(MMCs)brings down the production cost and the land pollution.Magnesium alloy AZ31 was reinforced with FA particles(10 vol.%)successfully by two different processing methods namely conventional stir casting and friction stir processing(FSP).The microstructural features were observed using optical microscope,scanning electron microscope and electron backscatter diffraction.The sliding wear behavior was tested using a pin-on-disc wear apparatus.The stir cast composite showed inhomogeneous particle dispersion and coarse grain structure.Some of the FA particles decomposed and reacted with the matrix alloy to produce undesirable compounds.Conversely,FSP composite showed superior particle dispersion and fine,equiaxed grains by dynamic recrystallization.FA particles encountered disintegration but there was no interfacial reaction.FSP composite demonstrated higher strengthening and wear resistance to that of stir cast composite.The morphology of the worn surface and the wear debris were studied in detail.

Improvement on Quantitative Measurement of Fly Ash Contents Using Laser-Induced Breakdown Spectroscopy

Contents of fly ash are important factors for the operation of coal-fired plants. Real-time monitoring of coal and fly ash such as unburned carbon in fly ash can be an indicator of the combustion conditions. Because of the strong signal intensity and the relative simplicity of the LIBS (Laser- Induced Breakdown Spectroscopy) technique, LIBS can be applicable for real-time composition measurement of coal and fly ash. This research presented here focused on the clarification of the effects of plasma temperature and coexisting materials on quantitative measurement of fly ash contents. Quantitative capability of LIBS was improved using the proposed plasma temperature correction method. The CO2 effect was also discussed to accurately evaluate unburned carbon in fly ash in exhausts. Using the results shown in this study, quantitative measurement of fly ash contents has been improved for wider applications of LIBS to practical fields.

Self-shaping of bioinspired chiral composites

Self-shaping materials such as shape memory polymers have recently drawn considerable attention owing to their high shape-changing ability in response to changes in ambient conditions, and thereby have promising applications in the biomedical, biosensing, soft robotics and aerospace fields. Their design is a crucial issue of both theoretical and technological interest. Motivated by the shape-changing ability of Towel Gourd tendril helices during swelling/deswelling, we present a strategy for realizing self-shaping function through the deformation of micro/nanohelices. To guide the design and fabrication of selfshaping materials, the shape equations of bent configurations, twisted belts, and helices of slender chiral composite are developed using the variation method. Furthermore, it is numerically shown that the shape changes of a chiral composite can be tuned by the deformation of micro/nanohelices and the fabricated fiber directions. This work paves a new way to create self-shaping composites.

DECAY OF VORTEX VELOCITY AND DIFFUSION OF TEMPERATURE IN A GENERALIZED SECOND GRADE FLUID

The fractional calculus approach in the constitutive relationship model of viscoelastic fluid was introduced. The velocity and temperature fields of the vortex flow of a generalized second fluid with fractional derivative model were described by fractional partial differential equations. Exact analytical solutions of these differential equations were obtained by using the discrete Laplace transform of the sequential fractional derivatives and generalized Mittag-Leffler function. The influence of fractional coefficient on the decay of vortex velocity and diffusion of temperature was also analyzed.

Monte Carlo simulation of lattice analysis of complex LaCeTh0.1CuOy using ion bombardment technique

Ion bombardment analysis of perovskite materials is challenging owing to their peculiar structure.This shortcoming renders the reliability on the technique somewhat questionable.In this research,three structured modifications(i.e.,scan angle,low energy,and large ion bombardment)were adopted to improve the ion bombardment analysis of 99,999 ions using Monte Carlo simulations.The modified technique was used to analyze the effects of a chemically pressurized‘‘A’’site in the perovskite lattice system.The LaCeTh0.1Cu2Oy compound was used in this experiment.Despite the low probing energy,it was observed that the high number of ions bombarding the material resulted in external pressure on the lattice structure of the material.Moreover,the chemically pressurized‘‘A’’site perovskite material was characterized by lattice mismatch,lattice fluctuations,grain boundary collapse,and oxygen displacement.The novel discovery of this research is the inter-and intra-extended lattice mismatches that are likely to connect.Hence,further investigation of the connection between inter-and intraextended lattice mismatches is recommended as they may enable fabrication of room-temperature superconductors.

Degradation Diagnostics from the Subsurface of Lithium-Ion Battery Electrodes

Despite the long-established rocking-chair theory of lithium-ion batteries(LIBs),developing novel characterization methodology with higher spatiotemporal resolution facilitates a better understanding of the solid electrolyte interphase studies to shape the reaction mechanisms.In this work,we develop a Xenon ion plasma focused ion beam(Xe+PFIB)-based characterization technique to probe the cross-sectional interface of both ternary cathode and graphite anode electrodes,with the focus on revealing the chemical composition and distribution underneath the electrode surface by in-depth analysis of secondary ions.Particularly,the lithium fluoride is detected in the pristine cathode prior to contact with the electrolyte,reflecting that the electrode degradation is in the form of the loss of lithium inventory during electrode preparation.This degradation is related to the hydrolysis of the cathode material and the decomposition of the PVDF binder.Through the quantitative analysis of the transition-metal degradation products,manganese is found to be the dominant element in the newly formed inactive fluoride deposition on the cathode,while no transition metal signal can be found inside the anode electrode.These insights at high resolution implemented via a PFIB-based characterization technique not only enrich the understanding of the degradation mechanism in the LIBs but also identify and enable a high-sensitivity methodology to obtain the chemical survey at the subsurface,which will help remove the capacity-fade observed in most LIBs.

Optimizing Movement of Students from Hostels to Lecture Rooms in a Potential World Class University Using Transportation Model

Transportation issue is one of the significant zones of utilization of Linear Programming Model. In this paper, transportation model is utilized to decide an ideal answer for the transportation issue in a run of the mill world class university utilizing Covenant University as a contextual analysis. Covenant University is a potential world class University. The quick development of Covenant University Campus over the most recent fourteen years affects its transportation framework. This paper particularly takes a gander at streamlining the time spent by the students moving from their lodgings to lecture rooms. Google guide was utilized to figure the separation and time between every cause and every goal. North-west corner technique, Least Cost strategy and Vogel’s estimation technique were utilized to decide the underlying fundamental plausible arrangement (initial feasible solution) and MODI strategy was utilized to locate the ideal arrangement (optimal solution). The last outcome demonstrates that the development of understudies from hostel to lecture rooms can be streamlined if the total time spent is decreased.

Forced Vibration Numerical Analysis of Rectangular Elastic Orthotropic Damped Inclined Mindlin Plate Using Finite Difference Algorithm

Plates vibrate when load moves on them. In this paper, the dynamic response of Mindlin plate analytical model was converted to its numerical form using finite difference algorithm. The numerical model was analysed to ascertain the critical parameters contributing to the deflection of Mindlin plate under a moving load. The examination was more reasonable as in the likelihood of the plate laying on a Pasternak foundation was put into thought. Likewise the impact of damping was not dismissed. The plate considered in this paper was an inclined Mindlin plate, where the impacts of shear deformation and rotatory inertia were considered. The numerical equations were solved with the help of a developed computer program and Matlab. The results were consistent with what we have in the literature. The effects of the Pasternak foundation, damping, angle of inclination, and the moving load to the dynamic response of the elastic plate were exceptionally self-evident.

Influence of Halide Choice on Formation of Low-Dimensional Perovskite Interlayer in Efficient Perovskite Solar Cells

Recent advances in heterojunction and interfacial engineering of perovskite solar cells(PSCs)have enabled great progress in developing highly efficient and stable devices.Nevertheless,the effect of halide choice on the formation mechanism,crystallography,and photoelectric properties of the lowdimensional phase still requires further detailed study.In this work,we present key insights into the significance of halide choice when designing passivation strategies comprising large organic spacer salts,clarifying the effect of anions on the formation of quasi-2D/3D heterojunctions.To demonstrate the importance of halide influences,we employ novel neo-pentylammonium halide salts with different halide anions(neoPAX,X=I,Br,or Cl).We find that regardless of halide selection,iodide-based(neoPA)_(2)(FA)_((n-1))PbnI_((3n+1))phases are formed above the perovskite substrate,while the added halide anions diffuse and passivate the perovskite bulk.In addition,we also find the halide choice has an influence on the degree of dimensionality(n).Comparing the three halides,we find that chloride-based salts exhibit superior crystallographic,enhanced carrier transport,and extraction compared to the iodide and bromide analogs.As a result,we report high power conversion efficiency in quasi-2D/3D PSCs,which are optimal when using chloride salts,reaching up to 23.35%,and improving long-term stability.

End Point Force Control of a Flexible Timoshenko Arm

This paper discusses a force control problem for a flexible Timoshenko arm. The effect of shear deformation and the effect of rotary inertia are considered in Timoshenko beam theory. Most of the research about force control of the flexible arm is based on Euler Bernoulli beam theory. There are a few researches about force control of the flexible arm using Timoshenko beam theory. The aim of the force control is to control the contact force at the contact point. To solve this problem, we propose a simple controller using Timoshenko beam theory. Finally, we describe simulation results using a numerical inversion of Laplace transform carried out to investigate the validity of the proposed controller for the force control problem. The results of the time response show the transverse displacement, the angle of deflection, the slider position, the rotational angle and the contact force toward the desired their values.

Technical-economical optimization of horizontal axis wind turbines by means of the genetic algorithm

Wind turbine design is a trade-off between its potentially generated energy and manufacturing cost represented by the area of turbine surface in this research, and both factors are highly influenced by a number of design parameters. In this research, first, a weighted sum of these factors, with a negative weight for power, is assumed as the performance function to be minimized. Then, blade element modeling was performed for class NACA turbines to estimate the generated power based on the effective wind velocity in the area. As a novelty, a new algorithm based on fuzzy logic was proposed to determine the effective wind velocity by using the history of wind velocity in the area. The wind velocity, therefore, the generated power by a wind turbine, is largely dependent on its operation area. In the end, the genetic algorithm with decimal numeric genes was employed to determine the optimal design parameters of the turbine based on the recorded data. This study resulted in a computer program which integrated calculations of fluid dynamics into the genetic algorithm to optimally determine an appropriate turbine (its geometric parameters). The implementation of the proposed method on two different regions ended up with the design of the blade NACA5413 for Manjil and the blade NACA4314 for Semnan, both in Iran.

Monte Carlo Simulation of a Combined-Cycle Power Plant Considering Ambient Temperature Fluctuations

A combined-cycle power plant (CCPP) is broadly utilized in many countries to cover energy demand due to its higher efficiency than other conventional power plants. The performance of a CCPP is highly sensitive to ambient air temperature (AAT) and the generated power varies widely during the year with temperature fluctuations. To have an accurate estimation of power generation, it is necessary to develop a model to predict the average monthly power of a CCPP considering ambient temperature changes. In the present work, the Monte Carlo (MC) method was used to obtain the average generated power of a CCPP. The case study was a combined-cycle power plant in Tehran, Iran. The region’s existing meteorological data shows significant fluctuations in the annual ambient temperature, which severely impact the performance of the mentioned plant, causing a stochastic behavior of the output power. To cope with this stochastic nature, the probability distribution of monthly outdoor temperature for 2020 was determined using the maximum likelihood estimation (MLE) method to specify the range of feasible inputs. Furthermore, the plant was accurately simulated in THERMOFLEX to capture the generated power at different temperatures. The MC method was used to couple the ambient temperature fluctuations to the output power of the plant, modeled by THERMOFLEX. Finally, the mean value of net power for each month and the average output power of the system were obtained. The results indicated that each unit of the system generates 436.3 MW in full load operation. The average deviation of the modeling results from the actual data provided by the power plant was an estimated 3.02%. Thus, it can be concluded that this method helps achieve an estimation of the monthly and annual power of a combined-cycle power plant, which are effective indexes in the economic analysis of the system.

BIFURCATION OF FLOW AND MASS TRANSPORT IN A CURVED BLOOD VESSEL

A numerical analysis of flow and concentration fields of macromolecules in a slightly curved blood vessel was carried out. Based on these results, the effect of the bifurcation of a flow on the mass transport in a curved blood vessel was discussed. The macromolecules turned out to be easier to deposit in the inner part of the curved blood vessel near the critical Dean number. Once the Dean number is higher than the critical number, the bifurcation of the flow appears. This bifurcation can prevent macromolecules from concentrating in the inner part of the curved blood vessel. This result is helpful for understanding the possible correlations between the blood dynamics and atherosclerosis.

Interfacial engineering of heterostructured carbon-supported molybdenum cobalt sulfides for efficient overall water splitting

Constructing hetero-structured catalyst is promising but still challenging to achieve overall water splitting for hydrogen production with high efficiency.Herein,we developed a sulfide-based MoS_(2)/Co_(l-x)S@C hetero-structure for highly efficient electrochemical hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).The carbon derived from the filter paper acts as a conducting carrier to ensure adequate exposure of the active sites guaranteed with improved catalytic stability.The unique hierarchical nano-sheets facilitate the charge and ion transfer by shortening the diffusion path during electro-catalysis.Meanwhile,the robust hetero-interfaces in MoS_(2)/Co_(1-x)S@C can expose rich electrochemical active sites and facilitate the charge transfer,which further cooperates synergistically toward electro-catalytic reactions.Consequently,the optimal MoS_(2)/Co_(1-x)S@C hetero-structures present small over-potentials toward HER(135 mV@10 mA·cm^(-2))and OER(230 mV@10 mA·cm^(-2)).The MoS_(2)/Co_(1-x)S@C electrolyzer requires an ultralow voltage of 1.6 V at the current density of 10 mA·cm^(-2)with excellent durability,outperforming the state-of-the-art electro-catalysts.This work sheds light on the design of the hetero-structured catalysts with interfacial engineering toward large-scale water splitting.

温热弯曲成形过程中AZ31镁合金型材的微观织构演变

采用光学显微镜、X射线衍射仪和EBSD分析研究AZ31镁合金型材温热弯曲成形前后横截面外侧微观组织和织构的演变规律。结果表明:弯曲成形前,型材为(10 10)平行于挤压方向的线织构;弯曲成形后,型材线织构被削弱。弯曲过程中拉伸孪晶数量减少,由弯曲前的5.39%降低至弯曲后的2.22%;压缩孪晶增多,由弯曲前的0.141%增加至弯曲后的0.222%。挤压型材的大量拉伸孪晶使得应力集中,协同温度的影响,非基面滑移开动并协调了晶粒c轴的应变,因而提高型材的塑性变形能力。

AA1060铝合金和C1100工业纯铜搅拌摩擦点焊的演变性能（英文）

采用搅拌摩擦点焊技术连接纯铜(C11000)和纯铝(AA1060)板材,并表征了焊缝的演变性能。在不同转速和送入深度下,采用不同形状刀具制备点焊焊缝。在焊缝两边可观察到不同长度铜环,这表明铜向前挤压进入铝板,有助于得到高强焊缝。采用能量散射谱和X射线衍射研究手段可观察到在铝基体中存在铜粒子,且有各种不同的金属间化合物存在。除了在转速800 r/min下采用锥形销和凹形肩得到的焊缝外,最大的拉伸断裂载荷随着送入深度的增加而增大。在剪切-拉伸载荷条件下,所有的搅拌摩擦点焊接头产生了点焊熔核滑脱失效模式。在样品锁眼附近得到了峰值硬度,这同焊接搅拌区存在金属间化合物有关。