Longitudinal and lateral slip control of autonomous wheeled mobile robot for trajectory tracking

This research formulates a path-following control problem subjected to wheel slippage and skid and solves it using a logic-based control scheme for a wheeled mobile robot (WMR). The novelty of the prop...     

Fatigue crack growth mechanism in cast hybrid metal matrix composite reinforced with SiC particles and Al2O3 whiskers

The fatigue crack growth (FCG) mechanism of a cast hybrid metal matrix composite (MMC) reinforced with SiC particles and Al₂O₃ whiskers was investigated. For comparison, the FCG mechanisms of a cast MMC with Al₂O₃ whiskers and a cast Al alloy were also investigated. The results show that the FCG mechanism is observed in the near-threshold and stable-crack-growth regions. The hybrid MMC shows a higher threshold stress intensity factor range, ΔK_th, than the MMC with Al₂O₃ and Al alloy, indicating better resistance to crack growth in a lower stress intensity factor range, ΔK. In the near-threshold region with decreasing ΔK, the two composite materials exhibit similar FCG mechanism that is dominated by debonding of the reinforcement–matrix interface, and followed by void nucleation and coalescence in the Al matrix. At higher ΔK in the stable- or mid-crack-growth region, in addition to the debonding of the particle–matrix and whisker–matrix interface caused by cycle-by-cycle crack growth at the interface, the FCG is affected predominantly by striation formation in the Al matrix. Moreover, void nucleation and coalescence in the Al matrix and transgranular fracture of SiC particles and Al₂O₃ whiskers at high ΔK are also observed as the local unstable fracture mechanisms. However, the FCG of the monolithic Al alloy is dominated by void nucleation and coalescence at lower ΔK, whereas the FCG at higher ΔK is controlled mainly by striation formation in the Al grains, and followed by void nucleation and coalescence in the Si clusters.     

Synthesis temperature dependence of morphologies and properties of cobalt oxide and silicon nanocrystals

Cobalt and cobalt oxide nanocrystals were synthesized on Si substrates from aqueous cobalt nitrate [Co(NO₃)₂·6H₂O] powder via chemical vapor deposition method. Scanning electron microscope, field emission scanning electron microscope, and transmission electron microscope observations show different morphologies, such as continuous films, nano-bars, nano-dices, and nano-strings, depending on the synthesis temperature. The crystal structure characterization was conducted using X-ray diffraction methods. Furthermore, the properties of the samples were characterized using Raman spectroscopic analysis and vibrating sample magnetometer. The morpholo- gy change was discussed in terms of synthesis environments and chemical interactions between cobalt, oxygen, and silicon.     

Self-assembled nanofilm of 1,2-dihydro-3-(octadecylthio)benzotriazine on copper for corrosion protection

The self-assembled nanofilm of 1,2-dihydro-3-(octadecylthio)benzotriazine (DOTBT) was formed on fresh copper surface obtained by etching with 7 N nitric acid at a room temperature of 30 °C. The conditions for formation of the DOTBT nanofilm have been optimized by electrochemical impedance and electrochemical quartz crystal nanobalance (EQCN) studies. The DOTBT nanofilm on copper surface was characterized by contact-angle measurement, X-ray photoelectron spectra (XPS), reflection absorption FTIR spectra and atomic force micrographs (AFM). It is inferred that formation of DOTBT film is due to chemisorption of DOTBT on copper surface through nitrogen and subsequent complex formation between DOTBT and Cu ⁺ ions. Corrosion protection ability of DOTBT nanofilm was evaluated in dilute aqueous NaCl solution using electrochemical impedance, potentiodynamic polarization, weight-loss and XPS studies. These studies inferred that the DOTBT film protects effectively copper from corrosion. Potentiodynamic polarization studies revealed that the DOTBT film inhibits corrosion by controlling the cathodic reaction. The mechanism of corrosion protection of copper by DOTBT nanofilm is discussed in this paper.     

Effect of fluxing additive on sintering temperature, microstructure and properties of BaTiO3

Various fluxing materials are added to technical ceramics in an attempt to lower their sintering temperatures and make their processing economical. The effect of 0·3?wt% Li₂CO₃ addition on the phase, microstructure, phase transition temperatures and dielectric properties of BaTiO₃ was investigated in the present study. The addition of 0·3?wt% Li₂CO₃ was observed to lower the optimum sintering temperature by ??200°C with no second phase formation and cause a five-fold reduction in grain size. Rhombohedral-to-orthorhombic and tetragonal-to-cubic phase transitions at the expected temperatures were evident from the Raman spectra, but the orthorhombic-to-tetragonal phase transition was not clearly discernible. The persistence of various phase(s) at higher temperatures in the flux-added materials indicated that the phase transitions occurred relatively slowly. A decrease in dielectric constant of Li₂O-added BaTiO₃ in comparison to pure BaTiO₃ may be due to the diminished dielectric polarizability of Li^?+? in comparison to Ba^2?+?.     

iRNA-PseTNC: identification of RNA 5-methylcytosine sites using hybrid vector space of pseudo nucleotide composition

RNA 5-methylcytosine(m^5C)sites perform a major role in numerous biological processes and commonly reported in both DNA and RNA cellular.The enzymatic mechanism and biological functions of m^5C sites in DNA remain the focusing area of researchers for last few decades.Likewise,the investigators also targeted m^5C sites in RNA due to its cellular functions,positioning and formation mechanism.Currently,several rudimentary roles of the m^5C in RNA have been explored,but a lot of improvements are still under consideration.Initially,the identification of RNA methylcytosine sites was carried out via experimental methods,which were very hard,erroneous and time consuming owing to partial availability of recognized structures.Looking at the significance of m^5C role in RNA,scientists have diverted their attention from structure to sequence-based prediction.In this regards,an intelligent computational model is proposed in order to identify m^5C sites in RNA with high precision.Three RNA sequences formulation methods namely:pseudo dinucleotide composition,pseudo trinucleotide composition and pseudo tetra nucleotide composition are applied to extract variant and high profound numerical features.In a sequel,the vector spaces are fused to build a hybrid space in order to compensate the weakness of each other.Various learning hypotheses are examined to select the best operational engine,which can truly identify the pattern of the target class.The strength and generalization of the proposed model are measured using two different cross validation tests.The reported outcomes reveal that the proposed model achieved 3%better accuracy than that of the highest present approach in the literature so far.     

Bioactivity,in-vitro corrosion behavior,and antibacterial activity of silver–zeolites doped hydroxyapatite coating on magnesium alloy

Mg-based alloys received significant attention for temporary implant applications while, their applications have been limited by high degradation rate. Therefore, silver–zeolite doped hydroxyapatite (Ag-Zeo-HAp) coating was synthesized on TiO₂-coated Mg alloy by physical vapour deposition (PVD) assisted electrodeposition technique to decrease the degradation rate of Mg alloy. X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FE-SEM) images showed the formation of a uniform and compact layer of Ag-Zeo-HAp with a thickness of 15 μm on the TiO₂ film with a thickness of 1 μm. The potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) tests indicated that corrosion resistance of Mg-Ca alloy was considerably increased by the Ag-Zeo-HAp coating. The bioactivity test in the simulated body fluid (SBF) solution showed that a dense and homogeneous bonelike apatite layer was formed on the Ag-Zeo-HAp surface after 14 d. Investigation of antibacterial activity via disk diffusion and spread plate methods showed that the Ag-Zeo-HAp coating had a significantly larger inhibition zone (3.86 mm) towards Escherichia coli (E. coli) compared with the TiO₂-coated Mg alloy (2.61 mm). The Ag-Zeo-HAp coating showed high antibacterial performance, good bioactivity, and high corrosion resistance which make it a perfect coating material for biomedical applications.     

银-沸石掺杂羟基磷灰石镁合金涂层的生物活性、体外腐蚀行为和抗菌活性（英文）

Mg-based alloys received significant attention for temporary implant applications while, their applications have been limited by high degradation rate. Therefore, silver-zeolite doped hydroxyapatite(Ag-Zeo-HAp) coating was synthesized on Ti O_2-coated Mg alloy by physical vapour deposition(PVD) assisted electrodeposition technique to decrease the degradation rate of Mg alloy. X-ray diffraction(XRD) analysis and field emission scanning electron microscopy(FE-SEM) images showed the formation of a uniform and compact layer of Ag-Zeo-HAp with a thickness of 15 μm on the Ti O_2 film with a thickness of 1 μm. The potentiodynamic polarization(PDP) and electrochemical impedance spectroscopy(EIS) tests indicated that corrosion resistance of Mg-Ca alloy was considerably increased by the Ag-Zeo-HAp coating. The bioactivity test in the simulated body fluid(SBF) solution showed that a dense and homogeneous bonelike apatite layer was formed on the Ag-Zeo-HAp surface after 14 d. Investigation of antibacterial activity via disk diffusion and spread plate methods showed that the Ag-Zeo-HAp coating had a significantly larger inhibition zone(3.86 mm) towards Escherichia coli(E. coli) compared with the Ti O_2-coated Mg alloy(2.61 mm). The Ag-Zeo-HAp coating showed high antibacterial performance, good bioactivity, and high corrosion resistance which make it a perfect coating material for biomedical applications.镁基合金作为临时植入材料的应用受到了越来越多的关注,然而,由于其降解速率高,因此应用受到了限制。为了降低镁合金的降解速率,本文作者采用物理气相沉积(PVD)辅助电沉积技术在镀氧化钛(Ti O_2)的镁合金上涂覆掺银-沸石羟基磷灰石(Ag-Zeo-HAp)涂层。X射线衍射(XRD)分析和场发射扫描电镜(FESEM)图片显示,在厚度约为1μm的二氧化钛薄膜上形成了均匀且致密的Ag-Zeo-HAp涂层,厚度约为15μm。动电位极化(PDP)和电化学阻抗谱(EIS)测试表明,通过Ag-Zeo-HAp涂层,Mg-Ca合金的耐腐蚀性大大提高。模拟体液(SBF)浸泡测试生物活性试验结果表明,在14 d后的Ag-Zeo-HAp表面上形成了一层致密且均匀的类骨磷灰石层。采用琼脂扩散法和平板涂布法对抗菌活性进行研究。结果表明,与Ti O_2涂层的镁合金(2.61 mm)相比,Ag-Zeo-HAp涂层对大肠杆菌(E.coli)的抑制区(3.86 mm)明显增大。Ag-Zeo-HAp涂层具有良好的抗菌性能、良好的生物活性和耐腐蚀性,是生物医学应用的理想涂层材料。     

PREPARATION OF CLOVE BUDS DEODORIZED AQUEOUS EXTRACT (CDAE) AND EVALUATION OF ITS POTENTIAL TO IMPROVE OXIDATIVE STABILITY OF CHICKEN MEATBALLS IN COMPARISON TO SYNTHETIC AND NATURAL FOOD ANTIOXIDANTS

ABSTRACT

Antioxidative properties of prepared clove buds deodorized aqueous extract (CDAE) in chicken meatballs are studied. Total phenolic and flavonoid contents were found to be 271.9 ± 12.0 mg gallic acid equivalent per gram and 161.6 ± 7.7 mg rutin equivalent per gram CDAE, respectively. Chicken meatball samples were: (1) C (control, i.e., without CDAE), and those supplemented with 200 ppm of; (2) T1 (CDAE); (3) T2 (ascorbic acid); and (4) T3 (butylated hydroxyanisole [BHA] : butylated hydroxytoluene [BHT] = 1:1). Oxidative stability was assessed by measuring peroxide value (PV) and 2‐thiobarbituric acid reactive substances (TBARS) besides determination of color and sensory acceptability, over 12 days of chilled storage (8 ± 1C). All the treated samples showed higher induction period as well as lower PV and TBARS values than “C” throughout 12 days of storage (*P < 0.05). Color analysis showed that CDAE greatly improved redness of meatballs as compared with ascorbic acid and BHA‐BHT (*P < 0.05). Meanwhile, hedonic test indicated that treatment T1 did not affect sensory acceptability of chicken meatballs for all the tested attributes (color, aroma, taste, texture and overall acceptance) (*P > 0.05) up to comparable extent with T2 and T3.

PRACTICAL APPLICATIONS

The study provides a valuable method for the preparation of meatballs by replacing harmful synthetic antioxidants with natural ones with promising antioxidant and shelf‐life potential besides maintaining sensory attributes. This adaptation may result in massively enhanced consumption of these meatballs with disease‐preventive and health‐promoting effects. The main hurdle in commercialization of spicy meatballs is the pungent smell of spices as well as use of toxic organic solvents for extraction. The problem has been overcome by developing a method for the preparation of deodorized extracts in aqueous medium, which may significantly enhance the commercialization potential of meatballs and meatball‐based functional foods.     

Influence of cold plasma treatment on insecticidal properties of wheat seeds against red flour beetles

For the long-term fortification of warehoused crops, the insecticidal impact of cold plasma treated wheat seeds against red flour beetles are studied. In this study, the gain weight loss, mortality and repellency tests of cold plasma treated seeds are investigated and statistical analysis is carried out by SPSS software. Cold plasma treatment is carried out at 800 V for 1 and 4 min. The results show that the minimum grain weight loss is observed in plasma treated seeds as compared to controlled seeds. It is also observed that the mortality rate is minimum in the controlled seed while maximum at 4 min plasma treatment. Similarly, the repellent effect has a very small variation as compared to the controlled seed for Tribolium Castaneum. Therefore, plasma treatment can be considered as a practical and effective method for seed protection against red floor beetles particularly during long-term storage by controlling the insecticidal effects.