Development and tribological characterisation of nanostructured Zn-Ni and Zn-Co coatings: a comparative study

Zn-Ni and Zn-Co alloy coatings were electrodeposited on mild steel from sulphate-based baths. The morphology, microstructure, microhardness and tribological behaviours of the coatings have been studied and discussed. While the Zn-5wt-% Co layers presented a nanocrystalline simple nodular structure (45?±?5?nm), the Zn-14wt-% Ni showed a particular structure called cauliflower morphology (30?±?7?nm). The X-ray diffraction analysis showed that each of the electrodeposits was formed from zinc solid solution with a uniform zinc-cobalt intermetallic phase γ₂ (CoZn₁₃) for Zn-5wt-% Co alloy. However, a single γ-phase (intermetallic compound Ni₅Zn₂₁) was presented for the Zn-14wt-% Ni alloys. The Zn-14wt-% Ni films were found to be harder and rougher than the Zn-5wt-% Co layers. Plastic deformation and oxide layers production were the main wear mechanisms for the investigated coatings. The Zn-14wt-% Ni coatings were found to have the best wear resistance due to their microhardness and particular structure.     

High levels lycopene accumulation by Dietzia natronolimnaea HS-1 using lycopene cyclase inhibitors in a fed-batch process

In an attempt to accumulate lycopene in the bacterium Dietzia natronolimnaea HS-1 cultured in beet molasses, the influence of lycopene cyclase inhibitors on carotenogenesis (within the range 0–60 ppm) were evaluated. All inhibitors blocked the biosynthesis of canthaxanthin and resulted in accumulation of lycopene as the predominant carotenoid. As the final step of a study aiming at the optimization of culture conditions, a central composite design to a fed-batch process was applied to optimize the concentrations of lycopene cyclase inhibitors (within the range 0–50 ppm) in order to achieve high level accumulation of lycopene from D. natronolimnaea HS-1 cultured in beet molasses. On the basis of this approach, the optimum concentrations of lycopene cyclase inhibitors required to achieve the highest level of lycopene accumulation (8.26±0.17 mg/L) were determined as follows: imidazole, 24.74 ppm; nicotinic acid, 28 ppm; piperidine, 24.05 ppm; pyridine, 27.6 ppm; and triethylamine, 23.22 ppm.     

Sketch-based garment design with quad meshes

Garment creation continues to be the most tedious part of the virtual clothing process. In this paper, we present an easy to use sketch-based cloth modeling approach. Contours can be easily sketched on a mannequin to generate quad meshes to represent pieces of cloth already fitted and draped. Typically, the clothing process depends greatly on the meshing scheme that has to infer its geometry from the input boundary. Our quad meshing scheme is based on discrete Coons patches but with arbitrary boundary input. We also apply the permanence principle to our topological solution to allow more control over the influence of the input boundary polyline on the interior output polygonal mesh. This facilitates the creation of folds that are strongest in curvature at the boundary and which diminish towards the interior. The generated garments can then be easily animated in a simulation system based on finite elements, using a rediscretization of the generated mesh and a reconstructed metric of the cloth surface.     

An analysis of flexibility and quality improvement in a quality-adjusted EOQ model with finite-range stochastic lead-time

Traditional Economic Order Quantity (EOQ) model operates under a series of highly restrictive assumptions, including, but not limited to, the assumptions of deterministic lead-time, perfect quality, and constant setup cost. Many variants of the traditional EOQ model have been developed as a result of relaxing one or more of these assumptions. These variants include a quality-adjusted EOQ model with finite-range stochastic lead-time which relaxed the deterministic lead-time and perfect quality assumptions. Utilizing the basic framework of the quality-adjusted model, the authors also considered the option of investment to improve the quality and obtained closed form relationships for the quality-adjusted and quality improvement models. This paper extends the previous work by investigating two additional models; one aimed at improving flexibility, through setup reduction, and the second considering the strategy of simultaneous investment in flexibility and quality improvement. Analytical and numerical results are presented for both models. These results indicate that significant savings over the quality-adjusted EOQ model with finite-range stochastic lead-time are realized for both the flexibility improvement and simultaneous models.     

Asymptotic BEP and SEP of Quadratic Diversity Combining Receivers in Correlated Ricean Fading, Non?Gaussian Noise, and Interference

In this paper, we study the asymptotic behavior of the bit-error probability (BEP) and the symbol-error probability (SEP) of quadratic diversity combining schemes such as coherent maximum-ratio combining (MRC), differential equal-gain combining (EGC), and noncoherent combining (NC) in correlated Ricean fading and non-Gaussian noise, which in our definition also includes interference. We provide simple and easy-to-evaluate asymptotic BEP and SEP expressions which show that at high signal-to-noise ratios (SNRs) the performance of the considered combining schemes depends on certain moments of the noise and interference impairing the transmission. We derive general rules for calculation of these moments and we provide closed-form expressions for the moments of several practically important types of noise such as spatially dependent and spatially independent Gaussian mixture noise, correlated synchronous and asynchronous co-channel interference, and correlated Gaussian interference. From our asymptotic results we conclude that (a) the asymptotic performance loss of binary frequency-shift keying (BFSK) with NC compared to binary phase-shift keying (BPSK) with MRC is always 6 dB independent of the type of noise and the number of diversity branches, (b) the asymptotic performance loss of differential EGC compared to MRC is always 3 dB for additive white Gaussian noise but depends on the number of diversity branches and may be larger or smaller than 3 dB for other types of noise, and (c) not only fading correlation but also noise correlation negatively affects the performance of quadratic diversity combiners.     

QoS‐aware broadcasting in VANETs based on fuzzy logic and enhanced kinetic multipoint relay

Vehicular ad hoc networks (VANETs) are emergent concepts in terms of infrastructure‐less communication. The data dissemination is usually done using broadcast schemes. Data broadcast in VANETs is a challenging issue due to the high mobility vehicles and the varying density. On one hand, these vehicles have to share and disseminate the safety‐critical information, in real time, to other intended vehicles. On the other hand, the existing broadcast solutions do not succeed, till now, to fulfill VANETs requirements especially in terms of performance and QoS. In this paper, we propose a new QoS‐aware broadcast method in order to face VANETs communications challenges. We choose to adapt a concept originally devoted to mobile ad hoc networks (MANETs) and join it to other specific VANET techniques to introduce a new broadcasting protocol in the aim of optimizing QoS fulfilment. The proposed solution is fundamentally based on enhanced kinetic strategy assisted with fuzzy logic for QoS‐aware multipoint relay (MPR). The protocol efficiency is eventually tested through an experimental study and compared with existing methods. The results prove the over‐performance of the proposed solution.     

Extraction and functional properties of gelatin from the skin of cuttlefish (Sepia officinalis) using smooth hound crude acid protease-aided process

The characteristics and functional properties of gelatin from skin cuttlefish (Sepia officinalis) were investigated and compared to those of halal bovine gelatin (HBG). The gelatin extraction efficiency was improved by an acid-swelling process in the presence of smooth hound crude acid protease extract (SHCAP). The yields of gelatins from cuttlefish skin after 48 h with acid and with crude acid protease (15 units/g alkaline-treated skin) were 2.21% and 7.84%, respectively. The gelatin from skin cuttlefish had high protein (91.35%) but low fat (0.28%) contents. Compared to HBG, the cuttlefish-skin gelatin (CSG) has different amino acids composition than halal bovine gelatin. CSG contained slightly low hydroxyproline and proline (180‰) than HBG (219‰), whereas the content of serine was higher (49‰ versus 29‰). The gel strength of the gelatin gel from CSG (181 g) was lower than that of HBG (259 g) (p < 0.05) possibly due to lower hydroxyproline content. Cuttlefish-skin gelatin exhibited a similar emulsifying activity but greater emulsifying and foam stability than the halal bovine gelatin (p < 0.05). Foam formation ability, foam stability and water-holding capacity of CSG were slightly lower than those of the HBG, but fat-binding capacity was higher in the cuttlefish gelatin.     

Optimization of β-carotene production by a mutant of the lactose-positive yeast Rhodotorula acheniorum from whey ultrafiltrate

The present work investigated on carotenogenesis with high β-carotene content by a new isolated high-activity strain-producer Rhodotorula acheniorum mutant MRN in cheese whey ultrafiltrate. After a serial of UV, ethymethanesurfonate (EMS), and nitrosoguanidine (NTG) mutagenesis, a mutant named MRN of the red lactose-positive yeast strain R. acheniorum was obtained. Then, the effects of different growth medium factors on carotenoid production by this mutant at batch-scale level were identified and optimized by means of response surface methodology (RSM) in order to achieve high-level production of β-carotene. The optimum conditions required to achieve the highest level of β-carotene (262.12±1.01 mg/L) were determined as follows: whey ultrafiltrate (WU) lactose concentration 55 g/L, pH 5.85, ammonium sulfate concentration 3.5 g/L, temperature 23°C, and aeration rate 1.56 vvm. The medium optimization resulted in a 6.45-fold increase in volumetric production (262.12±1.01 mg/L) and a 4.62-fold increase in the cellular accumulation (10.69±0.19 mg/g) of β-carotene.