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Parametric analysis of ball milling condition on thermoelectric performance of Bi0.6FeCo3Sb12 skutterudite
No full textThe FeCo 3 Sb 12 skutterudite crystal was doped with Bi to act as a filler material for the Bi 0.6 FeCo 3 Sb 12 formulation. It was prepared by ball milling and spark plasma sintering. The microstructure and thermoelectric performance of the bulk skutterudite was evaluated as function of its mechanical alloying process, i.e. ball milling. Rietveld analysis of its XRD spectra indicated that The Bi doping on the Co 4 Sb 12 based skutterudite succeeded in partially filling the voids of the skutterudite, whilst the Fe doping partially substituted the Co sites in the lattice. This serves to simultaneously increase the electrical conductivity whilst reducing the thermal conductivity of the resulting skutterudite. The ball milling times was correlated to the resulting microstructure, and ultimately, its thermoelectric performance. It was found that the moderate milling times (at 15 h) resulted in the best electrical conductivity, given the homogenous distribution of particles. A Maximum ZT value was observed 0.18 for 10 h ball milled sample at 673 K, whilst almost the same value was achieved for the 15 h ball milled sample, i.e. ZT = 0.17 at 673 K. Beyond this milling time, agglomeration of particles after ball milling caused degradation in the overall thermoelectric performance. Thus, this paper presents a strategy optimize the mechanical alloying process parameters to provide improved thermoelectric performance
Internal and external factors of mental health disorders in a healthy sustainable soul according to islamic psychotherapy in smart campus perspective
No full textGod's Word s.w.t: Then set your face straight to the religion of Allah, the nature of Allah, which He created man above that nature; there is no change for the creation of the nature of God; that's a straight religion, but most people do not know it. Every child born is in a sacred state, then both parents make it Jewish, Christian or Majusi. (HR Bukhari from Abu Hurairah r.a). Every human being who has been born to this earth has been created in the natural state; his heart always wants to face his God and wants to follow his religion; and the nature that God has created in every human being will never change, it will still voice the command to always return to the truth of God. In the growth and development of human development since birth until adulthood, nature is often lacking attention. This causes them to be unable to participate in daily activities through words, deeds, attitudes and movements. Property is the thing that is always the goal of man in the world. It sometimes causes all human life to be attracted to its enjoyment. This causes far in the corner of the natural heart to feel bound, confused, crying and disappointed because it cannot move freely to the direction of God's pleasure s.w.t. This is what causes people to become anxious, anxious and frightened
A microfluidic Lab-on-a-Disc (LOD) for antioxidant activities of plant extracts
No full textAntioxidants are an important substance that can fight the deterioration of free radicals and can easily oxidize when exposed to light. There are many methods to measure the antioxidant activity in a biological sample, for example 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant activity test, which is one of the simplest methods used. Despite its simplicity, the organic solvent that has been used to dilute DPPH is easily evaporated and degraded with respect to light exposure and time. Thus, it needs to be used at the earliest convenient time prior to the experiment. To overcome this issue, a rapid and close system for antioxidant activity is required. In this paper, we introduced the Lab-on-a-Disc (LoD) method that integrates the DPPH antioxidant activity test on a microfluidic compact disc (CD).We used ascorbic acid, quercetin, Areca catechu, Polygonum minus, and Syzygium polyanthum plant extracts to compare the results of our proposed LoD method with the conventional method. Contrasted to the arduous laborious conventional method, our proposed method offer rapid analysis and simple determination of antioxidant. This proposed LoD method for antioxidant activity in plants would be a platform for the further development of antioxidant assay
Q-switched and mode-locked thulium-doped fiber laser with pure Antimony film Saturable absorber
No full textStable and compact Q-switched and mode-locked thulium-doped fiber laser (TDFL) is demonstrated by employing Antimony (Sb) film Saturable absorber (SA) in the ring cavity. The Sb film SA is fabricated by sputtering a thin layer of Sb element onto polyvinyl alcohol (PVA) thin film. Self-pushed TDFL Q-switched with repetition rate and pulse width of 14.5 kHz to 23.5 kHz and 11.6 μs to 4.9 μs respectively are obtained, as the pump power raises from the threshold (271 mW) to its maximum (399 mW). The TDFL Q-switched spectrum is centered at 1947 nm wavelength. At the maximum pump power (399 mW), the maximum peak power and the maximum pulse energy are obtained at 24.4 mW and 120.12 nJ respectively. Meanwhile, self-starting mode-locked TDFL emerges as the pump power varies from 454 mW to 582 mW. The TDFL mode-locked output spectrum is centered at 1914 nm wavelength. A nearly constant repetition rate of 8.65 MHz and pulse width of 64 ps are observed, as the pump power lifted to the maximum (582 mW). The results verify that the pure Sb PVA film SA is viable to construct stable and reliable short pulse laser in the 2-micron regime
Q-switched ytterbium-doped fiber laser via a thulium-doped fiber saturable absorber
No full textWe demonstrated a reliable and stable Q-switched ytterbium-doped fiber laser centered at 1069 nm by employing a segment of 11 cm thulium-doped fiber (TDF) as a saturable absorber (SA) in the ring cavity. The fiber SA has an optical absorption of 1.35 dB at the Q-switched operating regime. As we increased the pump power from 109 mW to the maximum available pump power of 206 mW, a consistent Q-switched laser with output power ranging from 1.8 to 4.8 mW was attained. The pulse width narrowed from 4.9 to 2.87 μs, whereas the repetition rate increased from 40 to 60.2 kHz. In addition, maximum pulse energy of 80.7 nJ and a maximum peak power of 28.1 mW were obtained at the maximum pump power. The signal to noise ratio (SNR) was around 47 dB. Our experimental study shows that a segment of TDF can be used as a Q-switcher in the 1 μm fiber laser cavity to facilitate a reliable and robust microsecond pulse generation
Aging- and thermal-annealing effects on the vibrational- and microstructural-properties of PECVD grown hydrogenated amorphous silicon carbon nitride thin films
No full textIn this work, the hydrogenated amorphous silicon carbon nitride (a-SiCN:H) thin films were grown by PECVD from the discharge of silane (SiH4), methane (CH4) and nitrogen (N2) gases. Thereafter, the stability of the bonding and microstructural properties with respect to the effects of aging (under atmospheric environment) and thermal annealing (under low and high N2 flow-rates) were investigated by using Fourier transform infrared (FTIR) and micro Raman scattering techniques. Analyses on the as-prepared films showed that the Si[sbnd]H, Si-OH, C[sbnd]H and N[sbnd]H vibrational bonds were stable even through prolong aging while that of Si[sbnd]C[sbnd]N and C[sbnd]N bonds increased and Si[sbnd]N bonds decreased after aging. Meanwhile, low temperature annealing were found to improve the film structure due to the out-diffusion process of N atoms from weak Si[sbnd]N and C[sbnd]N bonds and migration of these N atoms to form strong Si[sbnd]N and C[sbnd]N bonds as well as restructuring of dangling bonds to form new Si[sbnd]C bonds. Additionally, the graphitic phase was more prominent in the film grown at low N2 flow-rate upon annealing, especially when annealed at low temperature. The C[sbnd]N bonds in the graphitic phase were found to be weak and released N atoms even when annealed at low temperature. However, high temperature annealing was shown to remove the graphitic phases in the film structure
A Comparative Study on a Cationic Dye Removal through Homogeneous and Heterogeneous Fenton Oxidation Systems
No full textOxidative treatment of a cationic dye solution, methylene blue, was investigated using magnetite nanoparticles and goethite in heterogeneous Fenton-like reaction, and ferrous ions in homogeneous Fenton-reaction. The aim was to compare the degradation efficiencies of the studied catalysts for decolorization of methylene blue solution as the model organic pollutant. Response surface methodology (RSM) was applied to determine the optimal operational conditions for magnetite/H2O2 and goethite/H2O2 systems. The [H2O2] of 0.2 M, catalyst dosage of 1 g/L, pH 9.0 and reaction time of 5h were chosen by RSM. The pH value of 3.0 was used in the case of Fe+2/H2O2 system. The experimental results showed that homogeneous Fenton oxidation system was the most effective system under both acidic and neutral conditions but decreased at pH value of 9.0 due to the decrease in available Fe2+ ions in the solution and generation of ferric hydroxide sludge. Fe3O4/H2O2 system represented better removal efficiency than FeO(OH)/H2O2 system that could be attributed to the presence of FeII cations in magnetite structure and its larger surface area
Vibrio coralliirubri sp. nov., a new species isolated from mucus of red coral (Corallium rubrum) collected at Procida island, Italy
No full textStrain Corallo1T was isolated from mucus of red coral (Corallium rubrum) at Punta Pizzaco (Procida island, Naples, Italy). It was characterised as a Gram-stain negative, motile, rod-shaped bacterium. Strain Corallo1T was found to show positive responses for cytochrome-c oxidase, catalase, reduction of nitrate and nitrite, β-galactosidase activity and hydrolysis of starch, xylan, peptone, Tween 40, Tween 80 and casein. Strain Corallo1T was found to be mesophilic, neutrophilic to alkalophilic and slightly halophilic. According to analysis of the almost-complete 16S rRNA gene, strain Corallo1T is closely related to Vibrio celticus (100% sequence similarity), Vibrio gigantis (100%), Vibrio crassostreae (99.7%), Vibrio artabrorum (99.7%) and Vibrio pomeroyi (99.6%). MLSA of five housekeeping genes (atpA, pyrH, recA, rpoA and rpoD) was performed to refine the phylogenetic relationships of strain Corallo1T. A draft genome sequence of strain Corallo1T was obtained. The DNA G+C content of this strain was determined to be 44.5 mol %. The major cellular fatty acids of strain Corallo1T are C16:1, n-C16:0 and C18:1, and the major isoprenoid ubiquinone is Q8. ANI indexes, in silico estimations of DDH values and wet lab DDH values demonstrated that strain Corallo1T represents an independent genomospecies. Based on a polyphasic taxonomic characterisation, strain Corallo1T is concluded to represent a novel species of the genus Vibrio, for which the name Vibrio coralliirubri sp. nov. is proposed. The type strain is Corallo1T (= DSM 27495T = CIP 110630T)
Code-switching practices in a Malaysian multilingual primary classroom from teacher’s and students’ perspectives
No full textThis study investigates a teacher's and three students' perspectives on shared instances of code-switching practices in a Malaysian multilingual primary classroom. It seeks to explore and compare whether students perceive the same benefit of code-switching as the teacher does. This bridges the gap of previous studies, which mostly either focused on teachers' or students' perspectives on code-switching. Three 11-year-old multilingual students with different levels of English proficiencies and a multilingual teacher were selected as participants for this study. Four hours of English lessons were audio-recorded, and field notes were taken occasionally throughout classroom observations. An individual interview session was conducted with the teacher, and a group interview was conducted with the student participants. The findings showed that the teacher's code-switching practices helped clear the students' doubts, reinforced their learning, and encouraged student participation in English lessons. One participant shared the same perspective of code-switching as the teacher did. The other two participants, however, only found it beneficial when the teacher practised code-switching for explanations, especially when constructing simple sentences. Both of these students reported that too much repetition of some words bore them as these were previously learned words. The study concludes that not all the students rely on code-switching to assist them during English lessons
Impact of Channel, Stress-Relaxed Buffer, and S/D Si1−xGe x Stressor on the Performance of 7-nm FinFET CMOS Design with the Implementation of Stress Engineering
No full textStress-engineered fin-shaped field effect transistors (FinFET) using germanium (Ge) is a promising performance booster to replace silicon (Si) due to its high holes mobility. This paper presents a three-dimensional simulation by the Sentaurus technology computer-aided design to study the effects of stressors—channel stress, stress-relaxed buffer (SRB), and source/drain (S/D) epitaxial stress—on different bases of FinFET, specifically silicon germanium (SiGe) and Ge-based, whereby the latter is achieved by manipulating the Ge mole fraction inside the three layers; their effects on the devices’ figures-of-merits were recorded. The simulation generates an advanced calibration process, by which the drift diffusion simulation was adopted for ballistic transport effects. The results show that current enhancement in p-type FinFET (p-FinFET) with 110% is almost twice that in n-type FinFET (n-FinFET) with 57%, with increasing strain inside the channel suggesting that the use of strain is more effective for holes. In SiGe-based n-FinFET, the use of a high-strained SRB layer can improve the drive current up to 112%, while the high-strain S/D epitaxial for Ge-based p-FinFET can enhance the on-state current to 262%. Further investigations show that the channel and S/D doping are affecting the performances of SiGe-based FinFET with similar importance. It is observed that doping concentrations play an important role in threshold voltage adjustment as well as in drive current and subthreshold leakage improvements