Thermophysical Properties of Mixtures of Tetrahydropyran with Chlorobutanes

Densities and absolute viscosities for the binary mixtures containing tetrahydropyran and isomeric chlorobutanes have been determined at 298.15 and 313.15 K at atmospheric pressure. From the densities, excess molar volumes were calculated. On the other hand, excess volumes and absolute viscosities have been correlated using the Peng–Robinson–Stryjek–Vera (PRSV) equation of state and the Lee model, respectively.     

Controlled Delivery of Gentamicin Antibiotic from Bioactive Electrospun Polylactide‐Based Ultrathin Fibers

The purpose of this study was to generate ultrathin fibers based on polylactide (PLA) biopolyester with antimicrobial controlled release capacity to treat bacterial infections. To achieve this objective, gentamicin antibiotic was encapsulated into pure PLA fibers, a blend of PLA–collagen and coaxial fibers containing a skin of PLA and a core of collagen using the electrospinning technique. The morphology of the gentamicin‐loaded fibers and the antibiotic distribution within the fibers were examined by SEM and TEM. The drug delivery profile of the different electrospun fibers was analyzed using a spectrophotometric method. The performance for treating common possible post‐surgical infections was investigated against Staphylococcus epidermis, Pseudomonas aeruginosa and Escherichia coli. The morphology of the electrospun fibers as well as the hydrophilicity of the polymer blends ultimately determined the antibiotic release characteristics. The results indicated that such drug‐loaded fibers can serve as advanced delivery platforms with strong and timing controllable antibacterial properties.     

Variable Bit Rate Voice Using Hysteresis Thresholds

In this work we address the problem of statistically multiplexing a variable number of telephone calls via a limited number of channels. Terminals operate with voice activity and silence detectors, and the speech is encoded to a bit rate which is system state dependent. Growing from zero, calls in the system are admitted with a maximum bit rate (maximum quality) until the cutoff fraction of talkspurt (a front end clipping) reaches a certain threshold. At this point the voice bit rate of all transmitting terminals is reduced. If due to traffic fluctuations, the number of calls in progress decreases, then all voice terminals are allowed to operate at the maximum bit rate again. In order to avoid annoying effects to listeners, both the percentage of voice information that is lost and the mean number of changes in the bit rate per mean call holding time are constrained. The first constraint is strongly dependent on the encoding bit rate, and the second one is controlled by using a hysteresis threshold when switching from one bit rate to another. In this work we have used three encoding bit rates, high, medium and low. A birth–death Markov process is used to model the system, which provided exact numerical evaluations for the percentage of time the system operates in each encoding bit rate and for the mean number of changes in the bit rate. Metrics are defined to measure the percentage of both types of voice information that are lost (not transmitted), cutoff or front end clipping and uniform dropping. Finally, an illustrative example is reported.     

Effects of high intensity pulsed electric field and thermal treatments on a lipase from Pseudomonas fluorescens

Milk and dairy products may contain microorganisms capable of secreting lipases that cause sensory defects and technological problems in the dairy industry. In this study, the effects of thermal and high-intensity pulsed electric field (HIPEF) treatments on an extracellular lipase from Pseudomonas fluorescens, suspended in a simulated skim milk ultrafiltrate (SMUF) have been evaluated. Heat treatments applied were up to 30 min from 50 to 90 degrees C. HIPEF treatments were carried out using pilot plant facilities in a batch or continuous flow mode, where treatment chambers consisted of parallel and coaxial configuration, respectively. Samples were subjected to up to 80 pulses at electric field intensities ranging from 16.4 to 37.3 kV/cm. This resulted in a lipase that was quite resistant to heat and also to HIPEF. High (75 degrees C-15 s) and low pasteurization treatments (63 degrees C-30 min) led to inactivations of 5 and 20%, respectively. Using the batch-mode HIPEF equipment, a 62.1% maximum activity depletion was achieved after 80 pulses at 27.4 kV/cm. However, when HIPEF treatments were applied in the continuous flow mode, an inactivation rate of just 13% was achieved, after applying 80 pulses at 37.3 kV/cm and 3.5 Hz. The results of both heat and HIPEF treatments on enzyme inactivation were adjusted with good agreement to a first-order kinetic model (R2 > 62.3%).     

Text mining for AI enhanced failure detection and availability optimization in production systems

The success of data-driven maintenance is strongly dependant on effective use of AI and multi-structured data sources. Introducing and integrating an AI-enhanced methodology in reliability-centred maintenance study of complex production systems leads to reducing failure rates and optimizing availability. In manufacturing enterprises, information about machine failures and expert knowledge are often stored in digital shift books (DSB). This paper introduces a transferable and scalable AI-enhanced methodology for DSB in automotive industry, which enhances Overall Equipment Efficiency (OEE) by optimizing availability through reducing the Mean Failure Detection Time (MFDT). Experimental investigations in the use-case suggest an OEE increase by over 5%.     

Survival, isolation and characterization of a psychrotrophic Bacillus cereus strain from a mayonnaise-based ready-to-eat vegetable salad

Incidence and population levels of Bacillus cereus in American salad, an industrially manufactured, packaged and refrigerated deli salad containing vegetables and mustard, were determined. Of 12 ready-to-eat samples examined, one (8.3%) was positive for B. cereus at less than 5 x 10(3)cfu g(-1). According to the ISO confirmation procedure, a strain was isolated and further characterized and identified as B. cereus EPSO-35AS by API 50CH/20E phenotypic system, combined with additional tests of motility, oxidase activity and anaerobic growth. This strain produced diarrhoeal enterotoxin in tryptic soy broth culture as detected by BCET-RPLA test, hydrolysed starch and had a low D(90)-value (2.1 min), with an estimated z-value of 6.79 degrees C. After a lengthy lag phase (9-12 days of incubation), the strain was able to grow at 8 degrees C in both nutrient broth and tyndallized carrot broth with specific growth rates from 0.009 to 0.037 h(-1), respectively. In the vegetable substrate, lag time was approximately 3 days (66 h) shorter than in laboratory medium. The effect of temperature abuses on the safety of the product during the time of use or consumption is discussed.