bluuebunny/crossref_metadata_2025 huggingface dataset:
Data acquisition system for capacitive energy storages
Authors: Gromov A B , Esafov A V , Fridman B E , Karpikov S R , Kuzmenkov V D , Serebrov R A , Shalaeva A I
Published: July 2020

Failures in capacitive energy storages result in destruction of faulty elements and other expensive components. Recovery of such failures requires long-term and expensive works to replace and to restore elements of the capacitive energy storage. Diagnostic hardware of the capacitive energy storages makes it possible to limit the consequences of such failures, to reduce the frequency of their occurrence, as well as to monitor the equipment and transmit information on functioning of the pulse current sources to the facility. The operation of data acquisition system in high voltage facilities is accompanied by the electromagnetic interference, and it is therefore necessary to provide the optical fiber transmission lines, the isolation of the diagnostics hardware components and galvanic isolation of their power supply.
The energy recovery sub-circuit for multiple stages of the stretch meat grinder with iccos circuit
Authors: Liu H , Peng X M , Bai P Y
Published: July 2020

The STRETCH meat grinder and the ICCOS are two typical inductive pulsed power supply circuits for electromagnetic launch system. On the basis of combing both, a new topology-STRETCH meat grinder with ICCOS-was put forward by Tsinghua University in 2013. After launching the railgun load, all of the remaining energy is stored in the energy transfer capacitor of the circuit. In this paper, the corresponding recovery circuit is designed for the circuit containing four STRETCH meat grinder with ICCOS circuits connected in a XRAM way in order to reuse the remaining energy. The prototype system has 4kA charging current, and thus 28.19kJ magnetic energy. More remaining energy can be recovered by triggering the related thyristors with more times. Simulation results show that the topology with the suggested energy recovery circuit can roughly recover 1/3 of the residual energy to the primary power and has potential prospects for high energy storage systems in the future.
Rapid recognition of laser-induced breakdown spectrum in laser damage
Authors: Chen Minhao , Li Wei , Yang Chunping
Published: July 2020

In this paper, the technology of rapid target recognition based on laser-induced breakdown spectroscopy (LIBS) data of target in the process of laser damage was studied. In terms of LIBS data classification, this paper used support vector machine (SVM), which was more advantageous in nonlinear and small sample cases, as the core algorithm. In order to solve the problem of large amount of high-precision LIBS data, which leaded to slow recognition, a segmented weighted peak intensity algorithm was proposed. Compared with the original data, the length of the spectrum vector constructed by this method can be reduced by about 10 times. Under the condition of ensuring the recognition accuracy, the recognition time of LIBS samples can be reduced by an order of magnitude. At the same time, the method can balance the recognition time and accuracy by adjusting the segment length, which has good flexibility and practicability.
Dynamic analysis of the primary breakup of an annular energetic liquid jet injecting into a confined space
Authors: Sun Ming-liang , Liu Ning , Zhang Xiang-yan
Published: July 2020

The Large Eddy Simulation (LES) with the Volume of Fluid (VOF) method was carried out to investigate the primary breakup dynamic mechanism of an annular energetic liquid jet injecting into a confined space. The gas vortex structure and the liquid jet formation were visualized by tracking the evolution of the phase velocity and the interface location, and hence the coalescence process of the goblet-shaped liquid jet from the annular liquid jet was reproduced. Simulation results indicate that the first coalescence is caused by the Rayleigh-Taylor instability, which is generated by the interaction between the liquid jet head and the gas in the confined space. Two kinds of large-scale vortex structure expedite the secondary coalescence and the final goblet-shaped liquid jet form. Cavities are observed on the dense liquid jet column as a result of the coalescence on the upstream. Consequently, the droplet breakup occurs more frequently on the downstream liquid jet under the gas phase disturbance. The viscous shear is created by the aerodynamic interaction, and the regular fish-scale structure is presented under the Kelvin-Helmholtz instability, which promotes the bulge surface to break into droplets. The research reveals the dynamic mechanism of the annular energetic liquid jet structural destabilization observed in the previous experiments. The combination of the structural instability and the surface instability facilitate the primary breakup of the annular energetic liquid jet, which is beneficial to improve the atomization and the combustion performance.
Numerical study of minute vortex generator jets in a turbulent boundary layer
Authors: PourRazzaghi M J , Xu C
Published: July 2020

The air-jet vortex generator has been proposed as a credible alternative to the more conventional vane vortex generator. Some numerical models of the flow in the neighborhood of these devices have been constricted to evaluate their potential benefits. The objective of this paper is to consider the effects of a single minute AJVG in a turbulent boundary layer on a flat plane and study the longitudinal vortex caused by merging two-minute co-rotating vortex in turbulent boundary layer. The flows were assumed fully turbulent and were solved using the finite volume, OpenFoam 5.0 on a structures grid, using SST k-ω turbulence model and standard wall functions. Predicted results were also validated with experimental data. A reasonably good match was served between the predicted and experimental Reynolds stress data. However, in compare of experimental data the longitudinal vortices were not remain along the stream and were disappeared early.
Research on muzzle response characteristics of automatic gun on launching based on rigid-flexible coupling dynamics
Authors: Li Y , Xie Y Y , Liu J , Wang K
Published: July 2020

In order to study the important influence for firing dispersion of muzzle response of automatic gun on launching, the rigid-flexible coupling dynamics model of automatic gun was established based on the rigid-flexible coupling system dynamics theory in software RecurDyn. And the flexible body of gun barrel assembly was set up by the modal synthesis method of dynamic sub-structure. The Hertz contact theory and flexible Bushing forces model were made equivalent to these constrained joints. According to the characteristic of automatic gun structure and continuous launching load, the dynamic vibrating response of simulation and analysis was made for the automatic gun on launching. The muzzle vibration response displacements in vertical and horizontal direction were obtained in the 300 rate of fire. Then the muzzle vibration velocity and acceleration with different structure clearance were also calculated by the finite element analysis program of the rigid-flexible coupling dynamics model of automatic gun. Through the comparison and analysis, the numerical solutions are closely matched with the experimental results. The results show that the vertical angle error of firing dispersion is less than 3.8% and the horizontal angle error is less than 10.2%. Thus, the simulation and experimental results verify the correctness and feasibility of this model. Further the structure design and optimization of automatic gun can be provided a reference foundation.
Research on fast switching interception of the real target
Authors: Wang T Y
Published: July 2020

In order to distinguish the decoy missile from the real in the middle of the ballistic missile flight, we proposed using image recognition and sliding-mode guidance in the kinetic energy interceptor terminal guidance phase. The paper set background on the kinetic energy interceptor in the middle course of ballistic missile flight. Due to the influence of the dummy target, the preset interception point is out of alignment and interceptors require terminal guidance adjustment. In this paper, two different global fast Terminal sliding modes are used to establish the intercept model equation. By simulink simulation comparison, it is found that the sliding mode guidance proposed in this paper can quickly and effectively switch interception orbit to hit the target.
The simulation study of damage assessment of a surface-to-air missile system attacked by an anti-radiation missile and the optimization of fuze-warhead coordination
Authors: Zhang Zh B , Wang Y Sh , Cao Y
Published: July 2020

The final damage effectiveness of warhead is the most important objective in missile system design. To obtain the damage probability of a certain anti-radiation missile warhead against a typical field surface-to-air missile system and find the optimal fuze-warhead coordination strategy, the studies of modelling, simulation and optimization are carried out. First, the vulnerability of the target is analysed and the target vulnerability model is established. Secondly, the calculation models of fragments field and over-pressure field are established to realize the calculation of encounter between warhead and target. Finally, the damage assessment model is established to calculate the damage probability of the parts and the whole system. Through Monte Carlo simulation, the single-shot damage probability of the missile is obtained when the parameters of the encounter between warhead and target are randomly selected according to a certain probability distribution. And the optimal fuze control strategies of the missile at different entrance angles are obtained through optimization calculation. If the entrance angle of the missile cannot be identified, the optimal fuze initiation strategy of the anti-radiation missile in this paper is a delay of 13ms. The results show that the research method of this paper can be applied to the missile weapon system with the function of entrance angle identification to maximize the damage efficiency.
Programming possibilities using MATLAB simulink embedded coder on the example of data analysis from ahrs module
Authors: Elert S
Published: July 2020

This paper shows capabilities to program Texas Instruments TMS320F2839xD DSP (Digital Signal Processor) using MATLAB Simulink Embedded Coder on the example of receiving and processing data from VN-100 AHRS module. The first part of article described specification of C2000 Delfino MCU F28379D LaunchPad development kit and AHRS module. Next part prensents physical connection VN-100 module with microcontroller and configuration method to setup MATLAB Simulink and Embedded Coder for selected microcontroller. Presented program in MATLAB Simulink shows communication between AHRS module. VN-100 and microcontroller treated as receiver. Also It shows how to generate code and described the basic functions that were used to run application. The designed system is explained as a photos from MATLAB and real tests. The last part of paper demonstrates graphic preview of microcontroller load possible during operation and advantages of programming using MATLAB Simulink Embedded Coder.
Error spectrum full range convergence technique for laser optics element
Authors: Wang Zh B , Zhang Y L , Jiao M Y , Zhang F , Zhang Zh
Published: July 2020

In the application of laser optics, it requires well surface roughness and profile to reduce the laser energy losing. Such as ultra-smooth processing technology is generally used for processing optical components to meet the surface quality requirements. However, traditional elevation parameters PV(Peak-Valley)/RMS(Root Mean Square) are not enough to meet the optics demand. Error Spectrum distribution is an important technical index to be concerned in the field of ultra-high power laser. Different spectral errors cause different laser energy losing. So it is necessary to explore the error full-spectral convergence processing technology. In this paper, basing on the discussion of error spectrum Evaluation methods, the full spectral range converges technology is introduced to meet the demands of high power laser.
Double Higgs production in the high- and low-energy limits
Authors: Davies Joshua
Published: July 2020

In this talk we discuss some of the computational aspects of some recent computations of double Higgs production in gluon fusion. We consider the challenges encountered in computing the high-energy limit of the NLO virtual corrections and the large top quark mass limit of the NNLO virtual corrections.
MCSANCee generator with one-loop electroweak corrections for processes with polarized e+e- beams
Authors: Sadykov R R , Arbuzov A B , Bondarenko S G , Dydyshka Ya V , Kalinovskaya L V , Novikov I I , Yermolchyk V L , Rumyantsev L A
Published: July 2020

A new Monte Carlo event generator MCSANCee for simulations of processes at future e+e− colliders is presented. Complete one-loop electroweak radiative corrections and polarization of the initial beams are taken into account. The present generator includes the following processes:

e
+

e
−

→

e
+

e
−

,

μ
+

μ
−

,

τ
+

τ
−

,
Z
H

. Numerical results for the

e
+

e
−

→
Z
H

process are shown. Plans for the further extension of the MCSANCee generator are discussed.
Computer algebra with Rings library
Authors: Poslavsky Stanislav
Published: July 2020

Implementation of modern algorithms in computer algebra requires the use of generic and high-performance instruments. Rings is an open-source library, written in Java and Scala programming languages, which implements basic concepts and algorithms from computational commutative algebra while demonstrating quite a high performance among existing software. It rigorously uses generic programming approach, providing a well-designed generic API with a fully typed hierarchy of algebraic structures and algorithms for commutative algebra. Polynomial arithmetic, GCDs, factorization, and Gröbner bases are implemented with the use of modern asymptotically fast algorithms. The use of the Scala language brings a quite novel powerful, strongly typed functional programming model allowing to write short, expressive, and fast code for applications in high-energy physics and other research areas.
Declarative analysis in “Troitsk nu-mass” experiment
Authors: Nozik Alexander
Published: July 2020

The modern scientific data processing is not only a collection of powerful algorithms but also a whole infrastructure of facilities for data reading, processing, and results output. As the amount of data grows, so grows a need for automation of the process. The proper automation requires not only improvement of existing frameworks, but also a search of new ways to organize data processing in a way it could be automated and parallelized. DataForge experimental framework solves some problems by making the analysis configuration declarative instead of imperative. In this article, we present a limited demonstration of the idea applied to “Troitsk nu-mass” experiment in the search for sterile neutrino.
An innovative monitoring and maintenance model for the INFN CNAF Tier-1 data center infrastructure
Authors: Ricci P P , Donatelli M , Onofri M , Scarponi L B , Velardo A
Published: July 2020

During the last years we have carried out a renewal of the Building Management System (BMS) software of our data center with the aim of improving the data collection capability. Considering the complex physical distribution of the technical plants and the limits of the actual building hosting our center, a system that simply monitors and collects all the necessary information and provides alarms only in case of major failures has proven to be unsatisfactory. In 2017 we suffered a major flood due to one main water pipeline failure in the public street. After this disastrous event, clearly far beyond our control, we were however forced to reconsider completely the physical site robustness of our building in addition to the current monitoring and alarm system capabilities. It was clear that in some specific cases, alerts should be triggered hours or days before the actual main problem arises in order to allow efficient human intervention and proper escalation process. This paradigm could be easily applied to almost all the infrastructure components in our site, mainly the electric power distribution and continuity systems as well as the whole cooling devices. For this reason, in parallel to a consistent increase in the sensor widespread distribution of our BMS data collector system, a study of a predictive maintenance approach applicability to our site has been started. Predictive maintenance techniques aims at prevent unexpected infrastructure components failures or major events with the study of the whole monitoring data collection and the creation of appropriate statistical models with the help of big data analysis and machine learning techniques. An improvement in the Power Distribution Units (PDUs) monitoring in our site and the introduction of a dedicated network of water leak sensors were the first steps for increasing the data collection information at our disposal. With sufficient monitoring statistical information stored in our BMS system a preliminary and exploratory predictive data analysis proof of concept could be constructed. This could lead to the model building phase and the creation of a prototype with the aim of forecasting future infrastructure main failure events and forthcoming error conditions. The general idea is, conceivably, an approach to the predictive maintenance model where it would be possible to introduce scheduled corrective actions for the purpose of preventing potential failures in the next future and increasing the site overall reliability.
Fips: An OpenGL based FITS viewer
Authors: Kornilov Matwey , Malanchev Konstantin
Published: July 2020

FITS (Flexible Image Transport System) is a common format for astronomical data storage. [1]. Even though astronomical data is now processed mostly using software, visual data inspection by a human is still important during equipment or software commissioning and while observing. We present Fips [2, 3], a cross-platform FITS file viewer released as open source software1. To the best of our knowledge, it is for the first time that the image rendering algorithms are implemented mostly on GPU (graphics processing unit). We show that it is possible to implement a fully-capable FITS viewer using OpenGL [4] interface, including movie support for representing 3D data. We also emphasise the advantages of using GPUs for efficient image handling.
A Virtualized Tier-3g Facility Installation for WLCG Network of CERN
Authors: Saygın H. , Kuday S. , Alici A. , Turk Cakir I.
Published: July 2020

A Tier-3g Facility within the computing resources of Istanbul Aydin University has been planned and installed with the TR-ULAKBIM national Tier-2 center. The facility is intended to provide an upgraded data analysis infrastructure to CERN researchers who are the members in the recent nation-wide projects and international projects such as ATLAS and CMS experiments. The fundamental design of Tier-3g has been detailed in this work with an emphasis on technical implementations of the following parts: Virtualization of all nodes, VOMS usage for reaching fast experimental data in the WLCG network, batch cluster / multicore computing with HTCONDOR and PROOF systems, usage of grid proxies to access code libraries in AFS and CVMFS, dynamic disk space allocation and remote system mounting of EOS. We also present the interpretation of test results that was obtained by the simulation of typical analysis codes.
New ROOT graphics language
Authors: Betsou Iliana , Linev Serguei , Bellenot Bertrand , Couet Olivier
Published: July 2020

In the context of ROOT7, the graphics system is completely redefined. Based on client server architecture and with the use of modern C++ and JavaScript, ROOT7 provides a new web based graphics system. The new concepts of ROOT7 can be displayed directly in the browsers using the new classes for opening a new web window, communicate with the server and exchange data between front and back end and JavaScript ROOT (JSROOT).
JupyterLab at the Saint Petersburg State University
Authors: Erokhin Andrey , Zarochentsev Andrey
Published: July 2020

This paper describes our experience using and extending JupyterLab. We started with a copy of CERN SWAN environment, but now our project evolves independently. A major difference is that we switched from classic Jupyter Notebook to JupyterLab, because our users are more insterested in text editor plus terminal workflow rather than in Notebook workflow. However, like in SWAN, we are still using CVMFS to load Jupyter kernels and other software packages, and EOS to store user home directories.
Overall quality optimization for DQM stage in High Energy Physics experiments
Authors: Benekos N , Parra-Royon M , Benitez J M
Published: July 2020

Data Acquisition (DAQ) and Data Quality Monitoring (DQM) are key parts in the HEP data chain, where the data are processed and analyzed to obtain accurate monitoring quality indicators. Such stages are complex, including an intense processing work-flow and requiring a high degree of interoperability between software and hardware facilities. Data recorded by DAQ sensors and devices are sampled to perform live (and offline) DQM of the status of the detector during data collection providing to the system and scientists the ability to identify problems with extremely low latency, minimizing the amount of data that would otherwise be unsuitable for physical analysis. DQM stage performs a large set of operations (Fast Fourier Transform (FFT), clustering, classification algorithms, Region of Interest, particles tracking, etc.) involving the use of computing resources and time, depending on the number of events of the experiment, sampling data, complexity of the tasks or the quality performance. The objective of our work is to show a proposal with aim of developing a general optimization of the DQM stage considering all these elements. Techniques based on computational intelligence like EA can help improve the performance and therefore achieve an optimization of task scheduling in DQM.
The DQM system for the SND detector
Authors: Pugachev K. V. , Kardapoltsev L. V. , Korol A. A.
Published: July 2020

The SND detector has been operating at the VEPP-2000 collider (BINP, Russia) for several years. We present its new DQM system.

The system deals with multiple parameters being numbers, histograms or user opinions to form a data quality decision (good, bad, etc). It calculates SND subsystem and overall statuses and produces summaries available via web-interface. The system supports multiple parameter sets for different usages like daily checks, precise subsystem control, preparing data for processing, etc. The parameter values are analyzed using special ROOT macros yielding quality checks that could be supplemented or corrected by users.

The system is a part of a new SND information system implemented as a web application using Node.js and MySQL. The ROOT macros are written by SND subsystems experts using a simple framework. Histograms are displayed using JSROOT.

The system is put into production. It is consistent, however there are some improvements to implement.
Next Generation of HEP CPU benchmarks
Authors: Giordano Domenico , Santorinaiou Evangelia
Published: July 2020

HEPSPEC-06(HS06) is a decade old suite used to benchmark CPU resources for WLCG. Its adoption spans from hardware vendors, to site managers, funding agencies and software experts. Although it is stable, reproducible and accurate, it is reaching the end of its life. Initial hints of lack of correlations with HEP applications have been collected. Looking for suitable alternatives the HEPiX Benchmarking Working Group has evaluated SPEC CPU 2017 with a number of fast benchmarks. The studies that have been done so far do not show any major advantage in adopting SPEC CPU 2017 with respect to HS06.

A suite based on workloads that HEP experiments run can be an alternative to industrial standard benchmarks. The adoption by LHC experiments of modern software development techniques simplifies the ability to package, distribute and maintain a field-specific benchmark suite. The HEPiX Benchmarking Working Group is actively working to make this possible.

This report summarises the progress of the HEPiX Benchmarking Working Group in building a benchmarking suite based on HEP workloads. Comparisons of results with SPEC CPU 2017 and HS06 will be discussed.
Parallelized Kalman-Filter-Based Reconstruction of Particle Tracks on Many-Core Architectures with the CMS Detector
Authors: Cerati G , Elmer P , Gravelle B , Kortelainen M , Krutelyov V , Lantz S , Masciovecchio M , McDermott K , Norris B , Reinsvold Hall A , Riley D , Tadel M , Wittich P , Würthwein F , Yagil A
Published: July 2020

In the High–Luminosity Large Hadron Collider (HL–LHC), one of the most challenging computational problems is expected to be finding and fitting charged-particle tracks during event reconstruction. The methods currently in use at the LHC are based on the Kalman filter. Such methods have shown to be robust and to provide good physics performance, both in the trigger and offline. In order to improve computational performance, we explored Kalman-filter-based methods for track finding and fitting, adapted for many-core SIMD (single instruction, multiple data) and SIMT (single instruction, multiple thread) architectures. Our adapted Kalman-filter-based software has obtained significant parallel speedups using such processors, e.g., Intel Xeon Phi, Intel Xeon SP (Scalable Processors) and (to a limited degree) NVIDIA GPUs. Recently, an effort has started towards the integration of our software into the CMS software framework, in view of its exploitation for the Run III of the LHC. Prior reports have shown that our software allows in fact for some significant improvements over the existing framework in terms of computational performance with comparable physics performance, even when applied to realistic detector configurations and event complexity. Here, we demonstrate that in such conditions physics performance can be further improved with respect to our prior reports, while retaining the improvements in computational performance, by making use of the knowledge of the detector and its geometry.
Selective background Monte Carlo simulation at Belle II
Authors: Kahn James , Kuhr Thomas , Ritter Martin
Published: July 2020

The Belle II experiment, beginning data taking with the full detector in early 2019, is expected to produce a volume of data ffty times that of its predecessor. This dramatic increase in data comes the opportunity for studies of rare previously inaccessible processes. The investigation of such rare processes in a high data-volume environment requires a correspondingly high volume of Monte Carlo simulations to prepare analyses and gain a deep understanding of the contributing physics processes to each individual study. This presents a signifcant challenge in terms of computing resource requirements and calls for more intelligent methods of simulation, in particular background processes with very high rejection rates. This work presents a method of predicting in the early stages of the simulation process the likelihood of relevancy of an individual event to the target study using convolutional neural networks. The results show a robust training that is integrated natively into the existing Belle II analysis software framework.
A 3D track finder for the Belle II CDC L1 trigger
Authors: Skambraks Sebastian , Bähr Steffen , Becker Jürgen , Kiesling Christian , McCarney Sara , Meggendorfer Felix , Tonder Raynette van , Lukas Unger Kai
Published: July 2020

Machine learning methods are integrated into the pipelined first level (L1) track trigger of the upgraded flavor physics experiment Belle II at KEK in Tsukuba, Japan. The novel triggering techniques cope with the severe background from events outside the small collision region provided by the new SuperKEKB asymmetric-energy electron-positron collider. Using the precise drift-time information of the central drift chamber which provides axial and stereo wire layers, a neural network L1 trigger estimates the 3D track parameters of tracks, based on input from the axial wire planes provided by a 2D track finder. An extension of this 2D Hough track finder to a 3D finder is proposed, where the single hit representations in the Hough plane are trained using Monte Carlo. This 3D finder improves the track finding efficiency by including the stereo sense wires as input. The estimated polar track angle allows a specialization of the subsequent neural networks to sectors in the polar angle.
Physics inspired feature engineering with Lorentz Boost Networks
Authors: Erdmann M , Geiser E , Rath Y , Rieger M
Published: July 2020

We present a neural network architecture designed to autonomously create characteristic features of high energy physics collision events from basic four-vector information. It consists of two stages, the first of which we call the Lorentz Boost Network (LBN). The LBN creates composite particles and rest frames from the combination of final state particles, and then boosts said particles into their corresponding rest frames. From these boosted particles, characteristic features are created and used by the second network stage to solve a given physics problem. We apply our model to the task of separating top-quark pair associated Higgs boson events from a

t

t
¯

background, and observe improved performance compared to using domain unspecific deep neural networks. We also investigate the learned combinations and boosts to gain insights into what the network is learning.
Fabrication and characterization of ultrathin spin-coated poly(L-lactic acid) films suitable for cell attachment and curcumin loading
Authors: Kulikouskaya Viktoryia , Chyshankou Ihnat , Pinchuk Sergei , Vasilevich Irina , Volotovski Igor , Agabekov Vladimir
Published: July 2020

In the present study, ultrathin poly(L-lactic acid) (PLLA) films were fabricated using the spin-coating technique. Physicochemical properties of the formed materials, including their morphology, thickness, transparency, and contact angle, have been studied. We determined that the morphology of PLLA films could be regulated by changing the polymer concentration and humidity. By altering the humidity, microporous and flat PLLA films can be fabricated. The obtained samples were subsequently used for culturing mesenchymal stem cells and fibroblasts. It has been determined that cells effectively adhered to prepared films and formed on them a monolayer culture with high viability. It has been shown that PLLA films are suitable for the entrapment of curcumin (up to 12.1 μm cm−2) and provide its sustained release in solutions isotonic to blood plasma. The obtained PLLA films appear to be prospective materials for potential application in regenerative medicine as part of cell-containing tissue engineered dressings for chronic wound treatment.
Effect of sterilization treatment on mechanical properties, biodegradation, bioactivity and printability of GelMA hydrogels
Authors: Rizwan Muhammad , Chan Sarah W , Comeau Patricia A , Willett Thomas L , Yim Evelyn K F
Published: July 2020

Gelatin methacryloyl (GelMA) hydrogel scaffolds and GelMA-based bioinks are widely used in tissue engineering and bioprinting due to their ability to support cellular functions and new tissue development. Unfortunately, while terminal sterilization of the GelMA is a critical step for translational tissue engineering applications, it can potentially cause thermal or chemical modifications of GelMA. Thus, understanding the effect of terminal sterilization on GelMA properties is an important, though often overlooked, aspect of material design for translational tissue engineering applications. To this end, we characterized the effects of FDA-approved terminal sterilization methods (autoclaving, ethylene oxide treatment, and gamma (γ)-irradiation) on GelMA prepolymer (bioink) and GelMA hydrogels in terms of the relevant properties for biomedical applications, including mechanical strength, biodegradation rate, cell culture in 2D and 3D, and printability. Autoclaving and ethylene oxide treatment of the GelMA decreased the stiffness of the hydrogel, but the treatments did not modify the biodegradation rate of the hydrogel; meanwhile, γ-irradiation increased the stiffness, reduced the pore size and significantly slowed the biodegradation rate. None of the terminal sterilization methods changed the 2D fibroblast or endothelial cell adhesion and spreading. However, ethylene oxide treatment significantly lowered the fibroblast viability in 3D cell culture. Strikingly, γ-irradiation led to significantly reduced ability of the GelMA prepolymer to undergo sol–gel transition. Furthermore, printability studies showed that the bioinks prepared from γ-irradiated GelMA had significantly reduced printability as compared to the GelMA bioinks prepared from autoclaved or ethylene oxide treated GelMA. These results reveal that the choice of the terminal sterilization method can strongly influence important properties of GelMA bioink and hydrogel. Overall, this study provides further insight into GelMA-based material design with consideration of the effect of terminal sterilization.
Late Neolithic and Chalcolithic maritime resilience? The 4.2 ka BP event and its implications for environments and societies in Northwest Europe
Authors: Kleijne Jos , Weinelt Mara , Müller Johannes
Published: July 2020

This paper deals with prehistoric communities at the end of the 3rd millennium BC in Northwest Europe in relation to the 4.2 ka BP climatic event. In particular, the question of the resilience of these communities to climatic change will be studied here by comparing various climatic records and analysing specific archaeological parameters for social and cultural change. These parameters include the duration and intensity of settlement occupation, the variability of subsistence activities (e.g.cereal cultivation, animal husbandry, hunting, fishing, and gathering) and the connectedness of communities within exchange networks. Rather than answering the often-asked yes/no question with regard to human–environment relations, our research asks what effect resulted from the 4.2 ka BP climatic event, and, from the perspective of resilience, how did communities adopt to these changes in their practices and cultural choices during the later 3rd millennium BC.

In short, we maintain that climate change took place at the end of the 3rd millennium BC, but the changes in humidity and temperature with their effects on vegetation were probably regionally varied across Northwest Europe. We also observe that the studied communities developed differently during the second half of the 3rd millennium BC. On the one hand, we identify new food storage and house building techniques in the Low Countries and Schleswig-Holstein and, on the other hand, substantiate population decrease on the Orkney Islands around 2300 BC. Finally, we note a development of the Bell Beaker phenomenon into an Early Bronze Agemaritoryof connected communities across the North Sea, in which these communities expressed their resilience to climate change.
Fuzzy node flow analysis of water distribution networks using Jaya algorithm
Authors: Sreethu S , Gupta Rajesh
Published: July 2020

Fuzzy analysis helps in understanding how the uncertainty in various independent parameters of water distribution network such as, nodal demands, pipe roughness values, reservoir heads, pipe diameters and so forth will affect the dependent parameters such as pipe velocities, discharges and nodal pressures. The membership functions of dependent parameters are obtained by considering membership functions of uncertain independent parameters. The Impact Table method from literature suggests a repetitive analysis by considering the monotonous relationship between dependent and independent parameters. The Impact Table method was also employed for carrying out fuzzy analysis under pressure deficient condition to obtain fuzzy membership function of nodal outflows. Optimization based methods of fuzzy analysis are more useful when relationship between dependent and independent parameters are non-monotonous. A novel algorithm, Jaya is used in this study for performing fuzzy analysis on a benchmark network by pressure dependent approach. The analysis is performed by setting up hydraulic model in the software EPANET and linking it with the MATLAB for performing optimization through an EPANET-MATLAB toolkit. The propagation of the uncertainties of the input parameters for some non-linear hydraulic responses were identified and the algorithm was found to be a powerful tool for optimization.
Incorporation of non-stationarity in precipitation intensity-duration-frequency curves for Kerala, India
Authors: Soumya R , Anjitha U G , Mohan Smitha , Adarsh S , Gopakumar R
Published: July 2020

Intensity-Duration-Frequency (IDF) curve is an essential hydrologic tool used for the design of hydraulic infrastructure. In a changing climate scenario, the assumption of a static return period of precipitation extremes is not valid; the under-estimation of rainfall intensity values may lead to the failure of critical infrastructure. This paper is focused on identifying the extent of non-stationary behaviour at different locations in Kerala. The annual maxima rainfall data prepared from daily time series was idealized into non-stationary Generalized Extreme Value (GEV) distributions, with time-varying parameters after rainfall disaggregation operation. Non-stationary rainfall intensities were estimated using different non-stationary models, and the best model was identified using Akaike Information Criteria (AIC). From the analysis using station-wise data, it was found that districts including Palakkad, Malappuram, Idukki and Pathanamthitta were experiencing significant non-stationarity in extreme precipitation events. Non-stationary rainfall extremes were concentrated at Eastern regions of Kerala compared to coastal and midlands of Kerala.
Partitioning behaviour of heavy metals in Ashtamudi estuary, india
Authors: Manaf Febina A , Priya K L
Published: July 2020

The pH, salinity, SSC and variations of heavy metals were studied for Ashtamudi estuary during the pre-monsoon period of 2019. Both pH and salinity decreased from the mouth of the estuary, while SSC exhibited a higher value within 4 to 10 Kms from the estuarine mouth. Concentrations of Fe, Cr, Cu, Zn and Ni decreased from the mouth towards the head of the estuary. Among which both Fe and Cr showed higher concentrations within 4 to 10 Kms. Variation of the distribution coefficients (Kd) of trace metals with pH, salinity and suspended sediments indicated lower values for Fe, Cr and Zn at the locations 2 and 3, . As the dissolved concentrations of Fe and Cr showed higher values at locations with higher SSC, adsorption and desorption studies were performed using sediments at those locations. Adsorption studies on Fe indicated higher adsorption at higher salinity values, while for Cr, the adsorption decreased with salinity. Kinetic adsorption and desorption studies for Fe and Cr indicated that the adsorption rates of Fe and Cr approached equilibrium after 2 hours and 1.5 hours respectively, while the desorption rates did not exhibit an equilibrium within the experiment duration. The results of kinetic sorption and desorption studies conducted for Fe and Cr exhibiting higher rate of adsorption for Fe and lower rate of adsorption for Cr at higher salinities, were in agreement with the higher Kd values of Fe and lower Kd values of Cr obtained from the field analysis.
Seismic analysis of plan irregular RC building frames
Authors: Krishnan P A , Thasleen N
Published: July 2020

The presence of irregularity in buildings is a matter of concern when it is subjected to devastating earthquakes. A sudden change in vertical or plan configuration in buildings tends to weaken the structure. To prevent failure and minimize the hazard potential of irregular buildings, the responses of such buildings to lateral loads have to be studied in detail. In this paper, the responses of irregular buildings are analyzed using Pushover analysis. 10 re-entrant corner models are analyzed to study their effect as per IS 1893 (Part 1): 2016 codal provisions. The analytical tools used include ETABS v 16.2.0 software and SeismoMatch 2018 software. The parameters considered in this study are storey displacement, stress concentration and performance levels. Strengthening techniques to strengthen vulnerable models are also discussed. The results obtained are compared with that of a regular structure.
A simplified procedure for the seismic analysis of RC moment resisting setback frames
Authors: Akhil S , Sajeeb R
Published: July 2020

Irregularity in elevation of buildings is increasingly popular in modern urban construction. One of the prominent forms of vertically irregular frames is the setback building frames. The seismic performance of buildings with irregular distribution of mass, stiffness, and strength along the height may be significantly different from that of regular buildings. The present paper focuses on quantification of irregularity and studying the effect of irregularity on the seismic performance of setback building frames. An index namely Geometric Regularity Index (GRI), calculated based on the geometric parameter of the building frame, is proposed in the study to quantify the vertical irregularity of setback building frames. 55 numbers of 3 bay frames with stories 5, 7, 9, 11 and 13, with varying levels of irregularity, are considered in the study. Linear dynamic analysis of the frames is performed in ETABS using response spectrum method. The proposed index is correlated with the actual seismic response of the structure such as base shear and overturning moment. Based on the results of analysis, a simple method which employs the GRI of the frame is proposed to estimate the seismic responses such as base shear and overturning moment at the base. The proposed method is found to estimate the seismic response of setback frames with reasonable accuracy.
A new ground motion prediction model for Northeast India (NEI) shallow crustal
Authors: Rahman T , Nunia Bindesh
Published: July 2020

In this paper, a new ground-motion prediction model (GMPE) for North-eastern India (NEI) is developed based on the available recorded events. NEI has already faced several high magnitude earthquakes (moment magnitude [Mw
]>7.0) during the period 1200 to 2018. It is difficult to develop GMPE and estimating the seismic hazard of NEI, due to sparse recorded strong motion database. To date, seismic hazard maps for NEI have not been prepared. All developed countries have developed seismic hazard maps for their cities using region-specific GMPE. So, to prepare the seismic hazard maps of NEI, a ground motion prediction model will be required. The success of earthquake hazard mitigation depends to a large extent on how accurately the ground motion hazard can be estimated at a vulnerable site. The GMPE developed in this study has been compared with other ground-motion models as well as with the available limited recorded strong motion database. Based on the comparison, it is observed that the new model is reasonably correct as the model is unbiased with respect to both magnitude and hypocentral distance. This model needs to be upgraded as and when more recorded strong ground motion database is available for this region.
A numerical study of fiber reinforced polymer laminate plates
Authors: Cisily Thomas Priscila , Bindu S
Published: July 2020

Layered composites are used in various engineering fields like the aircraft, marine, automotive, sports and health sectors. The widespread use of these materials can be attributed to its high stiffness, high strength-to-weight ratio, and ease of installation. Among the various layered composites, fiber-reinforced polymers (FRP) laminates have high strength and stiffness of its constituent fibers and low-density due to its matrix properties. FRP laminate consists of unidirectional plies that can be tailor-made to achieve desirable performance. The demand for layered composite materials has driven the need for development of efficient analytical tools for accurate prediction of its performance. The present paper provides an insight into the analysis of a laminate plate. The effect of the number of layers, aspect ratio and the stacking sequence on the transverse deformation of a laminate plate under bending is analyzed. It is observed that the transverse deflection of the plate decreases with an increase in the number of layers. Also, the increase in aspect ratio leads to an increase in the deformation of the plates.
Study of the mechanical and corrosion resistance properties of ferrocement
Authors: Sneha S S , Soman Karthika , Prajith C , Davis Aiswaria K , Dhanya B S
Published: July 2020

Ferrocement is a lightweight, homogeneous and versatile structural material which is made as a composite of wire mesh and tightly wound skeletal steel impregnated with cement mortar. Ferrocement excels reinforced concrete system because of the minimal formwork and scaffolding requirement, possibility of casting elements on ground at site, fast erection and decrease in time of construction, and savings in the overall cost. Even though ferrocement has been used for various applications since 1800s, the technology is not properly standardized and unconventional local construction practices continue to prevail. Due to this and the poor workmanship, the durability of ferrocement structures has become an issue. Factors such as the corrosion of mesh and or the skeletal reinforcement, improper mix design etc. lead to deterioration of ferrocement structures. The major corrosion prevention methods used in reinforced concrete systems are application of coating to the steel such as epoxy or cement polymer composite (CPC) coatings and use of corrosion inhibitor in the cementitious matrix. The present study evaluates the possibility of adoption of these corrosion prevention strategies in ferrocement. The objective of the study is to analyse the flexural and corrosion resistance behaviour of four different types of ferrocement systems. The systems studied include ferrocement with normal welded mesh in normal cement mortar(WM); CPC coated weld mesh in normal cement mortar (CPC); normal weld mesh in cement mortar with corrosion inhibitor (WM CI); and CPC coated weld mesh in cement mortar with corrosion inhibitor (CPC CI). The corrosion analysis is done by using half cell potential measurements following ASTM C876-15 and flexural analysis by flexural strength test following IS 516: 1959. The results indicate that usage of both corrosion inhibitor and CPC coating can prominently increase the durability of ferrocement structures.
Evaluation of the mechanical performance of M25 grade recycled aggregate concrete
Authors: Dhanya B S , Koshy Bino I , Jisha K V , Jayamohanan Aisu , Mathew Neethu
Published: July 2020

Recycling, sustainability and environmental stewardship are some of the concepts that are in the front line now-a-days. Some strategies that can be adopted in order to bring these concepts in to the construction processes are the efficient use of materials, use of recycled materials, reduction in the waste materials produced etc. Use of recycled concrete aggregates as a substitute for natural (virgin) aggregates is a way to bring in these concepts into the manufacture of concrete. An experimental investigation was conducted to assess the effect of replacement of normal coarse aggregate with recycled coarse aggregate (prepared from old concrete specimens) on M25 grade concrete. Different levels of replacements studied include 0%, 20%, 50%, 80% and 100% were considered. The properties studied are fresh properties as well as mechanical properties which include compressive strength, split tensile strength and flexural strength. It is concluded from the study that as the RCA content increases, it is necessary to increase the cement content and or to decrease the water cement ratio in order to attain target compressive strength.