Multi Step Research Articles

Multi step structural health monitoring approaches in debonding assessment in a sandwich honeycomb composite structure using ultrasonic guided waves

This paper aims to investigate the use of ultrasonic guided wave (GW) propagation mechanism and the assessment of debonding in a sandwich composite structure (SCS) using a multi-step approach. Towards this, a series of GW propagation-based laboratory experiments and numerical simulations have been carried out on the SCS sample. The debonding regions of variable size and locations were assessed using a pre-defined network of piezoelectric lead zirconate transducers (PZT). Besides, several artificial masses were also placed in the SCS to validate the multi-step structural health monitoring (SHM) strategy. The SHM approach uses a proposed quick damage identification matrix maps and an improved elliptical wave processing (EWP) strategy of the registered GW signals to detect the locations of debonding and other damages in the SCS. The benefit of the proposed damage identification map is to locate the damaged area (sectors) quickly. This identification step is followed by applying the damage localization step using the improved EWP only on the previously identified damage sector region. The proposed EWP has shown the potential to effectively locate the hidden multiple debonding regions and damages in the SCS with a reduced number of calculations using a step-wise approach that uses only a selected number of grid points. The paper shows the effectiveness of the proposed approach based on data gathered from numerical simulations and experimental studies. Thus, using the above-mentioned SHM strategy debondings and damages present within and outside the sensor network are localized. The results were cross verified with nondestructive testing (NDT) methods such as infrared thermography and laser Doppler vibrometry.

Application of 3D surface profilometer in single cut sample inspection

As a non-contact measuring instrument, 3D surface profilometer has many advantages such as high precision, good repeatability and high visualization, and has become the mainstream measuring equipment in the field of micro and nano detection. Single cut line sample, multi cut line sample and step sample have important applications in micro/nano calibration field. In this paper, 3D surface profilometer is used to measure two kinds of samples. The results are compared with those obtained by National Institute of Metrology. The results show that the results are similar to those obtained by other measuring equipment, which proves the powerful function of 3D surface profilometer.

A Study on Types of Cyber Crimes and Cyber Attacks Today

Abstract: With the increasing number of COVID-19 cases in the world and deaths worldwide has given a very worse condition to the whole world besides this covid pandemic there is also increase in number of Cyber-crimes and Cyber-attack of different types in the whole world. As Technology is advancing everyday there is a rise in Cyber-crime problem today, however security measures and prevention to protect this technology and the users of the technology is not advancing as quickly. So, the aim of this study is to understand and learn different types of Cybercrimes and Cyberattacks today in the world. It is important to prevent and to put awareness about the types of crimes and attacks. There are some protective procedures such as keep your software Up to date, Using of Anti-Virus Protection and also the use of Firewall, Continuously Changing Passwords and keep it as strong as can be, and also two step or multi step authentication should be done whenever necessary. Keywords: Cyber-crimes, Cyber-attacks, Types of Cyber-crimes, Prevention Measures, Threats

Application of a 3D printed miniaturized hydrocyclone in biopharmaceutical industry-numerical and experimental studies of yeast separation from fermentation culture media

Various industries ranging from water purification to pharmaceutical production have experienced multi separation steps that impose more process time and contamination possibility by batch operation. We propose a developed microfluidic particle sorter (miniaturized hydrocyclone) that adopts centrifugal force as it has ability to decline the number of separation steps and the risk of extrinsic contamination in continuous process. While biological industries have not relied on mini hydrocyclones considerably because of low efficiency and microfabrication difficulties, current work has been planned to conquer these obstacles. In this research, biomass separation from fermentation broth by 3 mm hydrocyclones was investigated. The effect of apex size, feed flow rate, hydrocyclone geometry were analyzed numerically in four mini-hydrocyclones. The most efficient mini-hydrocyclone was chosen to be made by elegant additive manufacturing technology and studied experimentally. The separation efficiency was achieved up to 90% while the concentration ratio of heavy stream (apex) to dilute stream (vortex finder) was reached more than twofold. The mini hydrocyclone performance in view of energy target was studied by Euler-Reynolds-Efficiency plots. The 4 μm cut size was achieved that is promising high throughput separation for biological particles.

Vertical power flow forecast with LSTMs using regular training update strategies

The strong growth of renewable energy sources as well as the increasing amount of volatile energy consumption is leading to major challenges in the electrical grid. In order to ensure safety and reliability in the electricity grid, a high quality of power flow forecasts for the next few hours are needed. In this paper we investigate forecasts of the vertical power flow at transformer between the medium and high voltage grid. Forecasting the vertical power flow is challenging due to constantly changing characteristics of the power flow at the transformer. We present a novel approach to deal with these challenges. For the multi step time series forecasts a Long-Short Term Memory (LSTM) is used. In our presented approach an update process where the model is retrained regularly is investigated and compared to baseline models. The model is retrained as soon as a sufficient amount of new measurements are available. We show that this retraining mostly captures changes in the characteristic of the transformer that the model has not yet seen in the past and therefore cannot be predicted by the model without an update process. To give more weight to recent data, we examined different strategies in terms of the number of epochs and the learning rate. We show that our new approach significantly outperforms the investigated baseline models. On average, we achieved an improvement of about 8% with the regular update process compared to the approach without update process.

Continuous multi-step pumping of the optical clock transition in alkaline-earth atoms with minimal perturbation.

A suitable scheme to continuously create inversion on an optical clock transition with negligible perturbation is a key missing ingredient required to build an active optical atomic clock. Repumping of the atoms on the narrow transition typically needs several pump lasers in a multi step process involving several auxiliary levels. In general this creates large effective level shifts and a line broadening, strongly limiting clock accuracy. Here we present an extensive theoretical study for a realistic multi-level implementation in search of parameter regimes where a sufficient inversion can be achieved with minimal perturbations. Fortunately we are able to identify a useful operating regime, where the frequency shifts remain small and controllable, only weakly perturbing the clock transition for useful pumping rates. For practical estimates of the corresponding clock performance, we introduce a straightforward mapping of the multilevel pump scheme to an effective energy shift and broadening of parameters for the reduced two-level laser model system. This allows us to evaluate the resulting laser power and spectrum using well-known methods.

On the effect of zeolite acid property and reaction pathway in Pd–catalyzed hydrogenation of furfural to cyclopentanone

Aqueous phase hydrogenative rearrangement of furfural (FAL) to cyclopentanone (CPO) via furfuryl alcohol (FOL) has been studied over Pd catalysts supported on H–ZSM–5 zeolites. Pd states, zeolite properties and reaction condition parameters were optimized, affording 98% selectivity and 120 h−1 specific reaction rate over 2% Pd/H–ZSM–5(25) catalyst at 160 °C and 3 MPa H2. For hydrogenation of FAL–to–FOL, the activity was related to the Si/Al ratio and acid property of zeolite supports. For hydrogenative rearrangement of FOL–to–CPO, pure H–ZSM–5 zeolite could catalyze single–step conversion with relatively low reaction rate, whereas the presence of Pd sites could achieve multi–step transformation with remarkably increased rate, highlighting Pd–zeolite acid sites synergy. Proton and furanylmethoxy–relevant intermediates were captured with spin trapping electron paramagnetic resonance experiments, and 4–hydroxy–2–cyclopentenone and 2–cyclopentenone were also identified as key intermediates in tandem reaction pathway to produce CPO.

Synthesis and evaluation of antifungal activity studies of novel 2-(2-pyridyl)-2H-pyrazole-3-carboxamide derivatives

Background: Invasive fungal infections have negative impact on the health of immunocompromised individuals. With the development of fungal resistance to currently available antifungal drugs, there is a need to develop novel compounds with antifungal activity. Aims and Objectives: The objectives of the study are as follows: (1) To synthesize novel 2-(2-pyridyl)-2H-pyrazole-3-carboxamide derivatives and (2) to evaluate the antifungal activity of novel 2-(2-pyridyl)-2H-pyrazole-3-carboxamide derivatives. Materials and Methods: Novel 2-(2-pyridyl)-2H-pyrazole-3-carboxamide derivatives were prepared by multi step synthesis and characterized by LC-MS, 1HNMR and 13C NMR. The antifungal activity of these derivatives was assessed using Fusarium oxysporum, Aspergillus flavus, and Candida albicans by disc diffusion method. Results: We have synthesized fourteen derivatives of 2-(2-pyridyl)-2H-pyrazole-3-carboxamide. Most of the compounds possess good antifungal activity against F. oxysporum and C. albicans strains. Conclusion: We synthesized a series of novel 2-(2-pyridyl)-2H-pyrazole-3-carboxamide derivatives having good antifungal activity against F. oxysporus and C. albicans using a simple and low cost procedure.

Asynchronous Non–uniform Distributed Multi–target Tracking Filter Based on Asymmetric Alpha–divergence Consensus

With more and more extensive application of target tracking, distributed multi–target tracking (DMT) becomes an important research direction. However, the synchronization characteristics of some sensor networks can not be guaranteed due to communication delay, non–uniform sampling and so on. Therefore, a DMT algorithm for asynchronous non–uniform multi–sensor networks is studied in this paper. Firstly, by using the cardinalized probability hypothesis density (CPHD) based on continuous–discrete multi–target dynamic (CD) model (CD-CPHD), a CD–CPHD algorithm with multi–step birth process and time–triggered structure (TCD–CPHD) is proposed; Secondly, an asymmetric alpha–divergence (AAD) based adaptive computing structure of time–trigger index is designed to reduce the communication rate of TCD–CPHD; Thirdly, the fusion rule of AAD consensus is derived to construct the fusion process of the proposed algorithm; Finally, by combining the above structures and the fusion rule, the implementation process of the proposed algorithm is given. Theoretical analysis and exhaustive experimental analysis show the effectiveness of the proposed algorithm.

Project management in office: BIM implementation

Building Information Modelling (BIM) methodology is increasingly finding acceptance in all sectors of the construction industry including, as a first step, the architectural design, and after a set of multi activities concerning civil engineering (structures, building, budgeting, maintenance or operation). The elaboration of a complete project requires a BIM multi step workflow, including modelling, analysis, and the optimization of the final product that must be coordinated by a BIM manager. This new function within an enterprise, office or in single project is essential in a BIM context, as the main concept of the methodology is the centralization of all the information obtained throughout the elaboration of a complete project. The main competencies of a BIM manager: to deliver responsibility between all professional involved in a project; to authorize each expert to develop, change or transfer its project component; to indicate and control the level of information that a BIM model must include according to the Level of Development or Detail (LOD) established for each step of the project. The level of maturity of an enterprise or office is, in part, evaluated in a base of the integration of processes, using adequately the available BIM platforms, and in the level of collaboration established between the team regarding all the project process. The maturity achieved around the world is supported on governmental policies adopted by each country, in a mandatory or progressive way. The aspects related to the maturity achieved in an enterprise and the efficiency of the BIM manager work are the main objectives focused in the text. Several remarks were workout and presented, as a positive contribution to the dissemination of the BIM implementation in the sector.

Deep Learning-Based Predictive Framework for Groundwater Level Forecast in Arid Irrigated Areas

An accurate groundwater level (GWL) forecast at multi timescales is vital for agricultural management and water resource scheduling in arid irrigated areas such as the Hexi Corridor, China. However, the forecast of GWL in these areas remains a challenging task owing to the deficient hydrogeological data and the highly nonlinear, non-stationary and complex groundwater system. The development of reliable groundwater level simulation models is necessary and profound. In this study, a novel ensemble deep learning GWL predictive framework integrating data pro-processing, feature selection, deep learning and uncertainty analysis was constructed. Under this framework, a hybrid model equipped with currently the most effective algorithms, including the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) for data decomposition, the genetic algorithm (GA) for feature selection, the deep belief network (DBN) model, and the quantile regression (QR) for uncertainty evaluation, denoted as CEEMDAN-GA-DBN, was proposed for the 1-, 2-, and 3-month ahead GWL forecast at three GWL observation wells in the Jiuquan basin, northwest China. The capability of the CEEMDAN-GA-DBN model was compared with the hybrid CEEMDAN-DBN and the standalone DBN model in terms of the performance metrics including R, MAE, RMSE, NSE, RSR, AIC and the Legates and McCabe’s Index as well as the uncertainty criterion including MPI and PICP. The results demonstrated the higher degree of accuracy and better performance of the objective CEEMDAN-GA-DBN model than the CEEMDAN-DBN and DBN models at all lead times and all the wells. Overall, the CEEMDAN-GA-DBN reduced the RMSE of the CEEMDAN-DBN and DBN models in the testing period by about 9.16 and 17.63%, while it improved their NSE by about 6.38 and 15.32%, respectively. The uncertainty analysis results also affirmed the slightly better reliability of the CEEMDAN-GA-DBN method than the CEEMDAN-DBN and DBN models at the 1-, 2- and 3-month forecast horizons. The derived results proved the ability of the proposed ensemble deep learning model in multi time steps ahead of GWL forecasting, and thus, can be used as an effective tool for GWL forecasting in arid irrigated areas.

Architecture and physico-chemical properties of Bacillus amyloliquefaciens L-17 pellicle formed at the air–liquid interface

Bacillus amyloliquefaciens is a ubiquitous soil and plant-associated bacterial species which shows structural and adaptative responses to the environment. This present paper explores the ability of the strain L-17 to form subaerial biofilms on a liquid surface. Hydrophobic and non-wetting properties were observed for the rough top biofilm layer in contact with the air, which are quite different to the hydrophilic properties which were observed for the smooth biofilm layer in contact with the liquid. Both pellicle interfaces were visualized by scanning electron microscopy revealing a complex three-dimensional architecture composed of exopolymers organized in stacked fibrous network or sheet-like structures in the vicinity of the subaerial surface. Disruption of the extracellular matrix by combining physical and chemical treatments indicated that both loosely and tightly bound polysaccharides were found as major components of this complex pellicle. Proteins were also involved in the aggregation and cohesion of the matrix as multi extraction steps were needed to recover some tightly bounded proteins. This was confirmed by applying protease treatment which was able to significantly disrupt the pellicle. Overall results underline the ability of B.amyloliquefaciens L-17 to survive on air-liquid interfaces. This feature offers an interesting strategy to escape aquatic environments and develop aerial biofilm in response to environmental changes involving wet-dry cycles.

Multiplex Quantitative Real-Time Polymerase Chain Reaction and High-Resolution Melting Analysis for Identification of a Couple At-Risk of Having a Newborn with Severe Thalassemia

Many polymerase chain reaction (PCR)-based techniques have been used for routine diagnosis of α- and β-thalassemias. However, most require a multi step of post-PCR processes that are time-consuming and labor-intensive procedures. This study reported the successful use of multiplex quantitative real-time PCR (qPCR), with high-resolution melting (HRM) analysis for diagnosis of two common deletional α0-thalassemia (α0-thal) and 15 common β-thalassemia (β-thal) mutations, in order to identify a couple at-risk of having a newborn with severe thalassemia in the northern region of Thailand. With this approach, 22 (7.2%) of 306 couples were diagnosed as being at-risk for having a child with severe thalassemia, including three homozygous α0-thal, five homozygous β-thal and 14 Hb E (HBB: c.79G>A)/β0-thal disease. Our findings indicated that multiplex qPCR with HRM is applicable for routine molecular diagnosis in order to identify a couple at-risk of having a newborn with severe thalassemia, especially in an endemic region.

A non-integer step ratio parallel computing method for hybrid finite-element and discrete-element on multi-core computer

Commercial finite-element and discrete-element software usually adopts a unified computational time step and limit the number of our computer cores. In the face of large-scale with refined scale computing models, this will undoubtedly increase the time cost. The multi time step method of integer step ratio is a method to deal with this kind of problem. A non-integer ratio multi-time step computing method based on domain decomposition and subcycling method is proposed and applied to the finite-element and discrete-element engineering problems. The whole model is divided into finite-element method (FEM) subdomains and discrete-element method (DEM) subdomains according to the load balance of CPU. A coupling region between adjacent domains consists of multiple boundary nodes and particles based on the non-integer step ratio. Boundary data in coupling region are transferred through MPI communication protocol. This method can make full use of the advantages of multi-core computer and improve the calculation efficiency of engineering software.

A novel particle filtering for nonlinear systems with multi-step randomly delayed measurements

For nonlinear discrete-time systems where measurements can be randomly delayed by multiple sampling periods, measurements are dependent conditioned on the state trajectory, and the dependence becomes more complicated with the increase of step of random delay. A particle filtering for this system is developed, which is novel in that the likelihood is computed allowing multi step of delay and dependence of measurements. Multi step of delay is dealt with through utilizing the formula of total probability skillfully, and dependence is dealt with through estimating the filtering probability distribution of random delay. The novel particle filtering is applied to two examples to validate its effectiveness and superiority.

Translation, cross-cultural adaptation, reliability and construct validity of the Dutch Oxford Knee Score \u2013 Activity and Participation Questionnaire

BackgroundPatients undergoing total knee arthroplasty (TKA) tend to be younger and tend to receive TKA at an earlier stage compared to 20 years ago. The Oxford Knee Score – Activity and Participation (OKS-APQ) questionnaire evaluates higher levels of activity and participation, reflecting activity patterns of younger or more active people. The purpose of this study was to translate the OKS-APQ questionnaire into Dutch, and to evaluate its measurement properties in pre- and postoperative TKA patients.MethodsThe OKS-APQ was translated and adapted according to the forward–backward translation multi step approach and tested for clinimetric quality. Floor and ceiling effects, structural validity, construct validity, internal consistency and test–retest reliability were evaluated using COSMIN quality criteria. The OKS-APQ, the Oxford Knee Score (OKS), the Short Form-36 (SF-36), a Visual Analogue Scale (VAS) for pain and the Forgotten Joint Score (FJS) were assessed in 131 patients (72 preoperative and 59 postoperative TKA patients), and the OKS-APQ was administered twice in 50 patients (12 preoperative and 38 postoperative TKA patients), after an interval of minimal 2 weeks.ResultsFloor effects were observed in preoperative patients. Confirmatory factor analyses (CFA) indicated a good fit of a 1-factor model by the following indices: (Comparative Fit Index (CFI): 0.97, Tucker-Lewis Index (TLI): 0.96 and Standardized Root Mean Square Residual (SRMR): 0.03). Construct validity was supported as > 75% of the hypotheses were confirmed. Internal consistency (Cronbach α’s from 0.81 to 0.95) was good in the pooled and separate pre- and postoperative samples and test–retest reliability (Intraclass Correlation Coefficients (ICCs) from 0.63 – 0.85) were good in postoperative patients and moderate in preoperative patients. The standard Error of Measurements (SEMs) ranged from 8.5 – 12.2 and the Smallest Detectable Changes in individuals (SDCind) ranged from 23.5 – 34.0 (on a scale from 0 to 100).ConclusionsPreliminary findings suggest that the Dutch version of the OKS-APQ is reliable and valid for a Dutch postoperative TKA patient sample. However, in a preoperative TKA sample, the OKS-APQ seems less suitable, because of floor effects and lower test–retest reliability. The Dutch version of the OKS-APQ can be used alongside the OKS to discriminate among levels of activity and participation in postoperative patients.

Rapid fabrication of partially exfoliated graphite foil with 3D hierarchical structure and its application in electrochemical detection of olaquindox

An ultra-fast and controllable electrochemical method for preparation of partially exfoliated graphite foil (EG) was developed. The exfoliation process was realized in NaH 2 PO 4 aqueous by a multi potential step (STEP) technology. The EG electrode possesses a 3D hierarchical structure with the graphene-like nanosheets seamlessly linked with the graphite substrate. The EG electrode can be directly used as working electrode of electrochemical sensor. The performed sensor displayed high performance for electrochemical detection of olaquindox (OLA), with limit of detection (LOD) of 15 nM and a linear range of 0.05–18.0 μM. In this work, an ultra-fast (150 s) and controllable electrochemical method for preparation of partially exfoliated graphite foil (EG) was developed. The exfoliation process was realized in NaH 2 PO 4 aqueous by a multi potential step (STEP) technology. The graphite foil (G) was switched periodically between the mild oxidation potential and the reduction potential, avoiding completely exfoliation of the graphene sheets. The exfoliation degree of G electrode can be strictly controlled by the electrochemical parameters. The EG electrode possesses a hierarchical structure with the graphene-like nanosheets seamlessly linked with the graphite substrate, which can ensure its direct use as working electrodes for electrochemical sensors. Owing to its large surface area (6.1 times higher than G electrode), extremely low resistance ( R ct = 0.247 Ω), and promotion of adsorption of molecules, the EG electrode displayed surpassed catalytic effect toward the electrochemical redox of olaquindox (OLA). Based on the EG electrode, a high-performance electrochemical sensor for detection of OLA was constructed. The limit of detection (LOD) of the proposed sensor was achieved to be 15 nM (S/N=3), with a linear range of 0.05 – 18.0 μM and ultra-high sensitivity of 2.94 × 10 −3 A cm −2 μM −1 . Further, the low cost, flexible, small volume and easy integration make the EG electrode based sensor promise perspectives in the field of electroanalysis.

The Multi Steps Synthetic Methods of (±)-Indolizidine 209D as an Amphibian Natural Product in the Family of Alkaloids

(±)-Indolizidine 209D is one of the alkaloids isolated from the skin secretions of certain neotropical frogs and exhibit a range of pharmacological properties, including blocking neuromuscular transmission. Therefore, the synthesis of indolizidine 209D and more complex derivatives, have been the subject of several publications. The preparation pathways of indolizidine 209D and its derivatives are the subject of this review. In this paper, some highly regio- and stereoselective functionalization process were reviewed through the synthesis of the optically active (±)-indolizidine 209D.

A multi step inertial algorithm for approximating a common solution of split generalized mixed equilibrium and minimization problems

A multi step inertial algorithm for approximating a common solution of split generalized mixed equilibrium and minimization problems

A Multidisciplinary Approach to Evaluate the Effectiveness of Natural Attenuation at a Contaminated Site

This study evaluates the natural attenuation of chlorinated hydrocarbons as remediation action in a contaminated site downtown the city of Parma (Italy). To achieve this goal, a combination of new investigation methods (bio-molecular analysis, compound specific isotope analysis, phytoscreening) has been proposed. The approach (named circular multi step) allows to: fully understand the phenomena that occur at the study site, design new investigation activities, and manage best practices. Consequently, each step of the approach improves the conceptual and numerical models with new knowledge. The activities carried out at the study site allowed to detect a contamination of perchloroethylene in a large part of the city of Parma and, of main importance, underneath a kindergarten. The results of the study did not show significant natural attenuation of chlorinated hydrocarbons and that the detected contamination could refer to the same unknown contaminant source. Furthermore, the innovative phytoscreening technique was applied to assess the presence of chlorinated hydrocarbons at the ground level. The plume spread was estimated through numerical modeling starting from potential contaminant sources. This study enhances the knowledge of groundwater flow and contamination in Parma and allows authorities to design new investigation/reclamation activities through management actions.