Fully polynomial time approximation scheme for the weighted flow-time minimization on a single machine with a fixed non-availability interval

In a recent paper [Theoretical Computer Science 363, 257–265], He, Zhong and Gu considered the non-resumable case of the scheduling problem with a fixed non-availability interval under the non-resumable scenario. They proposed a polynomial time approximation scheme (PTAS) to minimize the total completion time.In this paper, we propose a fully polynomial-time approximation scheme to minimize the total weighted completion time. The FPTAS has O(n²/ε²) time complexity, where n is the number of jobs and ε is the required error bound. The proposed FPTAS outperforms all the previous approximation algorithms designed for this problem and its running time is strongly polynomial.     

Evaluation of Hard TiN Coatings by Depth Sensing Indentation and Scratch Testing Methods

The IAR Nanomechanical Probe (NMP) was used in the depth sensing indentation mode to evaluate the Vickers hardness (HV) and elastic modulus E of five commercial TiN coatings applied to a 17-4 PH stainless steel substrate. The HV values of the TiN layers at depth to thickness (DTT) ratios of less than 0.1 varied between about 28 and 39 GPa, depending on the deposition process. The elastic modulus was within the range of 300 to 400 GPa, corresponding to published values, at DTT ratios of less than or equal to 0.05. At higher DTT values, the elastic modulus decreased with increasing DTT ratio due to larger and larger interference from the less rigid stainless steel substrate. Depth sensing scratch tests were also performed on the samples to determine the critical load _crvalues needed to cause spallation of the coatings. For each coating, the interfacial fracture toughness K_ic was calculated from _crand used to describe the adhesive strength. Distinct differences between the K_ic values of the different samples were observed, reflecting differences in adhesive strength. The significance of these results is discussed in terms of the application of titanium nitride coatings to gas turbine engines.     

Low cost and high efficiency of single phase photovoltaic system based on microcontroller

This paper presents a theoretical and practical study of a single phase photovoltaic conversion system. It consists of a step down converter to charge a battery with the maximum power available from photovoltaic generator (PVG) and a single phase voltage source inverter (VSI) to produce a stable AC voltage (220 V/50 Hz) with lower total harmonic distortion (THD). A new perturb and observe algorithm is designed and implemented in a cheaper microcontroller PIC 16F876 where the duty cycle perturbation and the sampling period are selected to insure the stability of the PV system around the maximum power. The control strategy adopted for the inverter is the Selective Harmonic Eliminated Pulse Width Modulation (SHE PWM). The pulses are calculated and transferred on the PIC 16F876 memory. With this technique, inverter losses are decreased and the output voltage is easily filtered with a simple low pass filter producing a perfectly sine wave form voltage. The battery is sized to supply loads in non-sunny times.With optimization of its various components, the conventional single phase PV system has a low cost, high efficiency but also good power quality which represents a good opportunity to use it in many stand alone photovoltaic applications such as houses lighting. An experimental system has been made to demonstrate the efficiency of the photovoltaic system and to validate simulations done by Matlab–Simulink environment.     

Comparison of Linear,Widely Linear and Fresh Equalizers for FBMC-OQAM Systems with Different Numerologies

Wireless Personal Communications - Wireless sensor network (WSN) is a cost-effective networking solution for information updating in the coverage radius or in the sensing region. To record a real...     

Epidemiology and antibiotic resistance of Salmonella enterica Serovar Kentucky isolates from Tunisia: The new emergent multi-drug resistant serotype

Since 2002, the emergence of multidrug resistant Salmonella enterica serovar Kentucky (S. Kentucky) and the associated salmonellosis with treatment failure were declared in different parts of the world and were in most of the case contracted during travels to Northeast and Eastern Africa. In the present work, we reported an epidemiological study of S. Kentucky isolated from different environmental and clinical origins in Tunisia, using Pulsed-field gel electrophoresis (PFGE); Enterobacterial Repetitive Intergenic Consensus (ERIC-2) fingerprinting; Plasmid profiling; and antibiotic resistance profiles. ERIC-2 fingerprinting allowed the differentiation of 14 different patterns versus only 4 pulsotypes. Besides, a high proportion of strains were found to be nontypeable by XbaI-PFGE and/or by plasmid profiling (plasmid-free strains). The antibiotic resistance was mainly detected against streptomycin (80.7%), sulfonamides (42.1%) and tetracycline (15.7%). Furthermore, two avian strains were shown to be resistant to trimethoprim–sulfamethoxazole and three clinical strains have demonstrated multidrug-resistant phenotypes (against 5 to 10 antibiotics) and all of them exhibited resistance against nalidixic acid, ciprofloxacin, ofloxacin and tetracycline.ERIC-2 PCR was found to be the most discriminative. However, combination of the three typing methods offer a better mean for differentiating S. Kentucky isolates, monitoring the multiresistant types and determination of their origin.     

Oxidative Inactivation of SARS-CoV-2 on Photoactive AgNPs@TiO2 Ceramic Tiles

The current SARS-CoV-2 pandemic causes serious public health, social, and economic issues all over the globe. Surface transmission has been claimed as a possible SARS-CoV-2 infection route, especially in heavy contaminated environmental surfaces, including hospitals and crowded public places. Herein, we studied the deactivation of SARS-CoV-2 on photoactive AgNPs@TiO₂ coated on industrial ceramic tiles under dark, UVA, and LED light irradiations. SARS-CoV-2 inactivation is effective under any light/dark conditions. The presence of AgNPs has an important key to limit the survival of SARS-CoV-2 in the dark; moreover, there is a synergistic action when TiO₂ is decorated with Ag to enhance the virus photocatalytic inactivation even under LED. The radical oxidation was confirmed as the the central mechanism behind SARS-CoV-2 damage/inactivation by ESR analysis under LED light. Therefore, photoactive AgNPs@TiO₂ ceramic tiles could be exploited to fight surface infections, especially during viral severe pandemics.     

Characterisation of volatile compounds in Tunisian fenugreek seeds

In this study, we intend to develop a simple and fast analytical procedure to identify the volatile compounds implicated in the odour of Tunisian fenugreek (Trigonella foenum-graceum L.) seeds. Two procedures, solvent extraction and static headspace solid-phase microextraction (SHS-SPME), have been used under different conditions. The volatile compounds extracted were systematically identified using gas chromatography–mass spectrometry, based on their mass spectrum and Kovats index on two columns of different polarity. A total of 67 compounds were identified, some of them being reported for the first time in fenugreek seeds (e.g. several pyrazines, 2,5-dimethyl-4-hydroxy-3(2H)-furanone or 1-epi-cubenol). Methanol was found to be the preferred solvent for high and medium boiling point volatile compounds, such as sotolone and nitrogen compounds. For SHS-SPME, the fibre coated with divinylbenzene/carboxen/polydimethylsiloxane 2 cm was the most suitable for extracting volatile compounds from ground seeds. The efficiency of this fibre was confirmed by direct gas chromatography–olfactometry, with a global odour similar to that of fenugreek seeds.     

Real-time safety monitoring in the induction motor using deep hierarchic long short-term memory

The safety of industrial installations requires real-time monitoring of the occurrence of defects in induction machines that are widely used in this field. The implementation of this type of system typically needs to process a large amount of data provided by sensors and thus necessitates high computing mass, which complicates sensor utilization in real time. In this paper, we propose a hierarchical recurrent neural network by stacking two long short-term memory layers to form a single end-to-end network. Trained to establish complex temporal relations in raw time series signals. Those signals are directly provided by the sensors without any preprocessing or hand engineered features extraction. To train the network, we use the stator currents of a three-phase induction motor captured in a steady state. The currents represent several operation modes, which comprise the healthy and failed states with several types of mechanical defects, electrical defects, and combinations thereof. The experimental results were obtained using data from a real test bed to demonstrate the robustness and speed of the proposed approach for real-time monitoring of the operating status of an induction motor.     

Elimination of polyphenols toxicity from olive mill wastewater sludge by its co-composting with sesame bark

Olive mill wastes represent a significant environmental problem in Mediterranean areas where they are generated in huge quantities in a short period of time. Their high phenol, lipid and organic acid concentrations turn them into phytotoxic materials, but these wastes also contain valuable resources such as a large proportion of organic matter and a wide range of nutrients that could be recycled. Composting is one of the technologies used for the valorization of this effluent, producing a fertilizer useful for poor soils.The present work deals with the changes that occur in the content of phenolic compounds and the biotoxicity of the oxidized substrate which result from the composting of olive mill wastewater (OMW) sludge with sesame bark. The total organic matter decreased 52.72% while water-soluble phenol degradation decreased 72% after 7 months of processing. Gas chromatography coupled with mass spectroscopy was used to confirm the elimination of polyphenols during composting. Initially, the analysis showed three abundant polyphenolic compounds, one of which was identified as the 4-hydroxyphenyl-ethanol (tyrosol), a well-known antioxidant in OMW. After 7 months of composting, all of the phenolic compounds disappeared. The phytotoxic effects of OMW sludge, assessed by the plant index germination, increased during the composting to reach 80% after 210 days. This trend was confirmed by the correlation between physico-chemical and toxicity parameters. The results obtained confirmed the stability of the compost prepared from OMW sludge with sesame bark and indicated a gradual detoxification as the compost matured.     

Biological activity during co-composting of sludge issued from the OMW evaporation ponds with poultry manure-Physico-chemical characterization of the processed organic matter

Olive mill sludge (OMS), a by-product resulting from natural evaporation of olive oil processing effluent, poses a major environmental threat. A current cost-effective practice of OMS management is composting. A mixture of OMS (60%) with poultry manure (PM) was successfully composted for 210 days. During the process, effluents of olive oil mill and confectionary were used to keep moisture at optimal level (40-60%). Biological indicators reflecting stability of the compost (microbial biota respiration and enumeration, and germination index) were analysed for the assessment of the product quality. The composted mixture showed a high microbial activity with a succession of microbial populations depending on the temperature reached during the biodegradation. The pathogen content from PM decreased with composting as did phytotoxic compounds. Phenols and lipids were reduced, respectively, by 40% and 84% while germination index increased with composting progress. Fourier transform infrared (FTIR) spectroscopic analysis revealed that the final compost improved the aromatic content compared to the starting materials, with a decrease in aliphatic groups and a reduction in the easily assimilated components by the microflora acting during the biological process. The final compost was characterized by relatively high organic matter content (26.21%), a low C/N ratio (16.21), an alkaline pH (8.32), a relatively high electrical conductivity (9.21mS/cm) and a high level of nutrients. The germination index for Lepidium sativum L. was 87.71% after 210 days of composting, showing that the final compost was not phytotoxic.