The influence of local operating features on the cutting parameters in turning

The paper presents an algorithm and a method of correction of cutting speed for turning operations which has been established on the basis of catalogue data. This approach is based on the Taylor equation concerning cutting speed and tool life as well as on the assumption that each technological process is different.     

Adsorption properties of carbonized polyacrylonitrile deposited on γ-alumina and silica gel by precipitation polymerization

The precipitation polymerization method was used for the deposition of various contents of polyacrylonitrile on two oxide-type supports (γ-alumina and silica gel). The synthesized materials were characterized by thermal analysis performed in inert and oxidizing atmospheres. The mechanism of polyacrylonitrile decomposition was proposed. In order to gain effective adsorbents of volatile organic compounds the polyacrylonitrile/support composites were carbonized at elevated temperatures. The texture and morphology of the calcined materials were examined by low-temperature sorption of N₂ and scanning electron microscopy, respectively. An influence of thermal treatment conditions and carbonaceous species loading on adsorption capacity of methyl-ethyl ketone vapour was also determined. Attenuated total reflection Fourier transform infrared spectroscopy measurements revealed that the ladder-type polyacrylonitrile species formed above 250 °C and stable up to about 350–400 °C are the most effective sites for methyl-ethyl ketone sorption. The carbonaceous species dispersion was found to be an additional factor influencing the adsorption capacity of the carbonized polyacrylonitrile/support composites.     

Application of a Screen-Printed Sensor Modified with Carbon Nanofibers for the Voltammetric Analysis of an Anticancer Disubstituted Fused Triazinone

In this paper, we propose the first analytical procedure—using a screen-printed carbon electrode modified with carbon nanofibers (SPCE/CNFs)—for the detection and quantitative determination of an electroactive disubstituted fused triazinone, namely 4-Cl-PIMT, which is a promising anticancer drug candidate. The electrochemical performances of the sensor were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square-wave adsorptive stripping voltammetry (SWAdSV). The presence of carbon nanofibers on the sensor surface caused a decrease in charge-transfer resistance and an increase in the active surface compared to the bare SPCE. Under the optimised experimental conditions, the proposed voltammetric procedure possesses a good linear response for the determination of 4-Cl-PIMT in the two linear ranges of 0.5–10 nM and 10–100 nM. The low limits of detection and quantification were calculated at 0.099 and 0.33 nM, respectively. In addition, the sensor displays high reproducibility and repeatability, as well as good selectivity. The selectivity was improved through the use of a flow system and a short accumulation time. The SWAdSV procedure with SPCE/CNFs was applied to determine 4-Cl-PIMT in human serum samples. The SWAdSV results were compared to those obtained by the ultra-high-performance liquid chromatography coupled with electrospray ionization/single-quadrupole mass spectrometry (UHPLC-ESI-MS) method.     

Modeling and assessing an intelligent system for safety in human-robot collaboration using deep and machine learning techniques

Multimedia Tools and Applications - The introduction of technological innovations is essential for accident mitigation in work environments. In a human-robot collaboration scenario, the current...     

Availability analysis of design configurations to compose virtual performance-optimized data center systems in next-generation cloud data centers

Next-generation cloud data centers are based on software-defined data center infrastructures that promote flexibility, automation, optimization, and scalability. The Redfish standard and the Intel Rack Scale Design technology enable software-defined infrastructure and disaggregate bare-metal compute, storage, and networking resources into virtual pools to dynamically compose resources and create virtual performance-optimized data centers (vPODs) tailored to workload-specific demands. This article proposes four chassis design configurations based on Distributed Management Task Force's Redfish industry standard applied to compose vPOD systems, namely, a fully shared design, partially shared homogeneous design, partially shared heterogeneous design, and not shared design; their main difference is based on the used hardware disaggregation level. Furthermore, we propose models that combine reliability block diagram and stochastic Petri net modeling approaches to represent the complexity of the relationship between the pool of disaggregated hardware resources and their power and cooling sources in a vPOD. These four proposed design configurations were analyzed and compared in terms of availability and component's sensitivity indexes by scaling their configurations considering different data center infrastructure. From the obtained results, we can state that, in general, when one increases the hardware disaggregation, availability is improved. However, after a given point, the availability level of the fully shared, partially shared homogeneous, and partially shared heterogeneous configurations remain almost equal, while the not shared configuration is still able to improve its availability.     

Compendium About Multicomponent Interdiffusion in Two Dimensions

Interdiffusion between dissimilar solids can change the properties of joined materials. Although much work has been done to study experimentally and theoretically interdiffusion in one-dimensional (1-D) diffusion couples, studying interdiffusion in two-dimensional (2-D) or three-dimensional (3-D) solids remains a challenge. In this article, we report an experiment and develop a model to study interdiffusion in a multicomponent system of 2-D geometry. The results (concentration maps and profiles) are compared with data obtained by modeling and numerical simulations. It is assumed that the system satisfies Vegard’s rule and diffusion coefficients are composition dependent. To model the multidimensional diffusion with a drift, we take benefit of the concept of the drift potential. A nonlinear parabolic-elliptic system of strongly coupled differential equations is formulated and the implicit difference method, preserving Vegard’s rule, is applied in the simulations.

     

DCAV: A software system to evaluate next-generation cloud data center availability through a friendly graphical interface

To assess the availability of different data center configurations, understand the main root causes of data center failures and represent its low-level details, such as subsystem's behavior and their interconnections, we have proposed, in previous works, a set of stochastic models to represent different data center architectures (considering three subsystems: power, cooling, and IT) based on the TIA-942 standard. In this paper, we propose the Data Center Availability (DCAV), a web-based software system to allow data center operators to evaluate the availability of their data center infrastructure through a friendly interface, without need of understanding the technical details of the stochastic models. DCAV offers an easy step-by-step interface to create and configure a data center model. The main goal of the DCAV system is to abstract low-level details and modeling complexities, becoming the data center availability analysis a simple and less time-consuming task.     

decentralized observation and control of nonlinear interconnected systems

In this paper, we investigate the problem of H_∞ decentralized tracking control design with a decentralized observer for interconnected nonlinear systems which are characterized by the interconnection of N subsystems. Each subsystem is modeled by a linear constant part perturbed by an additive nonlinearity which is illustrated by the interconnection terms.The proposed feedback control scheme is developed to ensure the asymptotic stability of the augmented system, to reconstruct the non-measurable state variables of each subsystem, to maximize the nonlinearity domain, and to improve the performance of the model reference tracking control by using the H_∞ criterion despite the external disturbances.The proposed control approach is formulated in a minimization problem and derived in terms of linear matrix inequalities (LMIs) whose resolution yields the decentralized control and observation gain matrices.The effectiveness of the proposed control scheme is demonstrated through numerical simulations on a power system with three interconnected machines.     

Dynamic Accumulation of Volatile Compounds Between Olive Pulps and Stones and Its Relation with the Fatty Acids Content During the Oil Extraction Process of Ouslati and Chemlali Olive Fruits

The characterization of both volatiles and fatty acids of Tunisian olive varieties (Ouslati and Chemlali) is achieved in order to understand their correlation with the aroma accumulation via the lipoxygenase (LOX) pathway. The main identified volatiles in both crushed pulps and crushed stones are hexanal, E‐(2)‐hexenal, (Z)‐3‐hexen‐1‐ol, 1‐hexanol, and hexyl acetate. With regard to their fatty acid composition, results show that both de‐stoned (DOO) and conventional (COO) olive oils contain mainly unsaturated fatty acids. The results also show that oleic acid (C18:1) is the main fatty acid in both DOO and COO. Meanwhile, linoleic acid (C18:2) is present in a relatively higher percentage (5.2% and 19.8%, respectively, for Ouslati and Chemlali DOI) than linolenic fatty acid (C18:3) (<2%). The analysis of volatiles shows that more than 80% of total LOX‐compounds from both crushed pulps and crushed stones have linolenic acid as synthesis precursor despite its lower level (2%). Moreover, the contribution of olive parts in generating aroma is much higher in crushed pulps (more than 80%) than in crushed stones, which explains the fact that DOO, extracted from crushed pulps, contains the dominant amount of volatiles. Therefore, the obtained results promote both the consumption and the marketing of DOO. Practical Applications: The aroma and the organoleptic properties of olive oil are strictly correlated with both the olives quality and the extraction techniques used. Many technologies are developed to extract olive oil with highest quality. De‐stoned olive oil extraction process is one of these technical procedures. In the present work, the characterization of volatiles in pulp and stone separately provides important information about the contribution of olive constitutive parts on the accumulation of olive oil aroma during the oil extraction process.     

Triacylglycerol and Glycerophospholipid Identification and Accumulation During Ripening of Pistacia lentiscus L. (Lentisc) Fruit

Triacylglycerol (TAG) and phospholipid (PL) compositions of vegetable oils are considered a marker of quality and are often used in industry to control the purity of the oils and to detect adulteration. In this study, the TAG and PL composition of developing fruit of Pistacia lentiscus were investigated for the first time. The total TAG content was found to increase rapidly during fruit ripening from 105 to 966 mg/100 g of oil respectively between the 35th and the 175th day after fructification (DAF). During this period, 16 different molecular species of TAG were identified and quantified. POO was the major TAG from the second stage of maturation. Only four classes of PL were identified in the P. lentiscus oil: the phosphatidic acid (PA), the phosphatidylethanolamine (PE), the phosphatidylglycerol (PG) and the phosphatidylinositol (PI). The mass spectra obtained showed the presence of nine molecular species of PA, five species of PE and seven molecular species for each PG and PI classes. The total phospholipid content decreased rapidly during fruit ripening, from 45.5 % at the 15th DAF to 6.88 % at the 175th DAF.