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• DRFC solar-hydrogen: Off-grid irrigation for arid areas. • Cost-effective: 9% lower than diesel, COE $0.529, NPC $5365. • Zero emissions vs. diesel's 993 kg/year. • Steady fuel cell: Consistent hybrid power, resilient to seasonal shifts. • Global impact: Reclaim deserts, boost food security sustainably. This study focuses on the challenges of desertification and non-arable lands in off-grid remote areas with hot and arid climates. Despite the availability of groundwater, these areas require access to electricity at night to operate the water pumps to spray the crops due to high evaporation rates during the daylight. The absence of grid electricity necessitates the utilize of diesel generators to power irrigation systems, representing a significant contributor to climate change and the depletion of fossil fuel reserves. Addressing nocturnal electrification using sustainable solutions is crucial for reclaiming such areas and eliminating the environmental impacts of diesel generators. The study introduces a novel closed-loop Discrete Regenerative Fuel Cell (DRFC) solar-hydrogen storage irrigation system designed explicitly for nocturnal utilization in water-scarce regions to rectify this concern. The study then assesses its performance compared to a conventional diesel generator system when supplying a one kW water pump for a sample land area of 10 dunams. Using the HOMER Pro simulation tool, the simulation results strongly support the assertion that the PV-hydrogen irrigation system intended in this study exhibits superior techno-economic performance compared to the conventional diesel-irrigation system. A comprehensive analysis of the net present cost (NPC) and cost of energy (COE) between the two systems reveals that the proposed system achieves values of $0.529 and $5365, respectively. In contrast, the diesel system records values of $0.572 and $5796, respectively. These findings indicate a notable 9 % reduction in overall costs associated with implementing the proposed system. Additionally, the fuel cell showed stable performance across varying months which implies a consistent and reliable contribution to the overall electrical power generation within the hybrid system, regardless of seasonal fluctuations in solar power and temperatures. Furthermore, in terms of environmental impact, our findings highlight a significant advantage of the proposed system over the diesel generator. Specifically, the proposed system produces zero carbon emissions, while emissions from the diesel generator were notably higher at 993 kg/year. It is essential to emphasize that the integration of fuel cells into the proposed system holds the potential to offer a clean source of drinking water for farmers and workers in the area. The implications of these findings can help the research community develop and facilitate the reclamation process of agricultural lands worldwide that face similar challenges to the study region. This could lead to subsequent global environmental and economic benefits, such as reducing the spread of desertification, enhancing productivity, improving food security, promoting environmental sustainability, and creating economic opportunities. [ABSTRACT FROM AUTHOR]

• A 2DOF fractional order control of a nonlinear and unstable system is investigated in this paper. • Analytical model based method is developed to design the parameters of the fractional order PD controller. • The fractional order controllers of the inner and outer loops are tuned to have a constant phase margin of the open-loop. • Based on experiment on a real ball and beam system, performance of the proposed controller is highlighted. Control engineers and researchers face challenges to design an efficient controller for Ball and beam system due to its nonlinear and unstable properties. This paper investigates two Degrees of Freedom fractional order control of the ball and beam system. It involves the model based method to design controllers' parameters for the corresponding linear model. The fractional order controllers are specially tuned to have a constant phase margin of the open-loop. This characteristic ensures the robustness of the controllers to the variations of system gain. This paper presents a proper evaluation and comparison between integer and fractional order controllers. Performance of each controller is evaluated in terms of set-point tracking, disturbance rejection, and robustness. The comparison between two controllers is validated through both simulation and experimental results. Strengths and weaknesses in the real-time control are also indicated. [ABSTRACT FROM AUTHOR]

The influence of defocusing distance of the fiber laser welding on Ti-51at%Ni, Ti-28%atNb and Ti-30at%Ta shape memory alloys (SMAs) was investigated. These alloys were produced by powder metallurgy (P/M) and sintered by furnace and microwave processes. The experimental results showed that the furnace-sintered Ti-Ni welds have the maximum porosity density and the lowest weld quality. While, the microwave sintered alloys of Ti-Nb and Ti-Ta SMAs presented better weldability, even though porosities were still observed. Ti-Ta SMA showed the best welding quality compared with the other welded joints. It can be concluded that porosities play important role in the welding of powder metallurgy alloys and in order to achieve high-quality welds, the porosities should be minimized. [ABSTRACT FROM AUTHOR]

Highly aligned titania (TiO 2 ) nanotube (NT) arrays have been grown on titanium sheet by using a self organized anodic oxidation method at different potentials (34–74 V) in a NH 4 F and ethylene glycol based electrolyte. Two sets of TiO 2 NT arrays have been fabricated with and without using cooling systems. Without cooling system, the solution temperature is increased from 25 °C (room temperature) to 63 °C with increase of anodization potential from 34 to 74 V. The temperature has been maintained to 25 °C by using water based cooling system. In both sets of samples, the pore diameter of TiO 2 NT arrays increases with increase of anodization potential. The maximum pore diameter has been (outer: 224 nm, inner: 172 nm) achieved with TiO 2 NT arrays (at 74 V) without using cooling system. The photocatalytic activity of the TiO 2 NT arrays is evaluated by the decomposition of methanol by the use of Fourier transform infrared spectrophotometer. The TiO 2 NT (at 44 V) sample has been fabricated without using cooling system, which shows the higher photocatalytic activity than the sample at other potentials. Using cooling system, the TiO 2 NT (at 54 V) sample shows the higher photo-decomposing property than the sample at other potentials. The TiO 2 NT (at 54 V) sample with cooling system shows the higher rate (photocatalytic activity) constant ( k = 0.0216) than the TiO 2 NT (at 44 V) sample without using cooling system ( k = 0.0186). The photocatalytic activity has been correlated with the nanostructural variation of TiO 2 NT arrays at different potentials without (self-grown solution temperature) and with water based cooling systems. [ABSTRACT FROM AUTHOR]

From January 2017 - December 2019, 75 out of 850 (8.8 %) great hammerhead sharks from the Arabian Gulf had skin lesions of black irregular discolorations on the ventral surface of the head. The lesions consisted of pencil-like lineations often advancing forward by about 2 mm in back-and-forth looped scribbles often forming a relatively linear bands of about 5–7 cm wide. Similar lesions were also found in the blacktip reef shark from the same area within the same period, and consisted of straight to irregular black lines, extended indiscriminately across the skin of the sharks. Microscopic examination of the skin revealed the presence of dark-brown eggs exhibiting the spindle or ellipsoidal eggs characteristic of Huffmanela sp. The morphometrics of eggs from both hosts were similar (62.9–89.9 μm long and 29.3–56.1 μm wide). The eggshells were smooth with polar plugs protruding or not, with an abruptly truncated crown-like or shoulder-like collar surrounding the plug. The eggs were only found in the epidermal layer of the skin. Based on the unique morphometrics of the eggs, we report a new species, named: Huffmanela selachii n. sp.. This appears to be the first report of Huffmanela from either the great hammerhead shark or the blacktip reef shark, and the third reported Huffmanela in sharks from the Arabian Gulf. It is also one of few species reported from connecting waters of the greater Indian Ocean. This new finding contributes to our understanding of the diversity and ubiquity of Huffmanela sp. in marine creatures. [ABSTRACT FROM AUTHOR]

This work was carried out to investigate the comparative effects of phosphorus and boron doing in vapor–liquid–solid (VLS) growth. Doped Si microneedles were grown by VLS mechanism at the temperature of 700 °C or less using Au as the catalyst. VLS growth using in-situ doping with the mixed gas of Si 2 H 6 and PH 3 produced phosphorus doped n-Si microneedles at Au dot sites, whereas, the mixed gas of Si 2 H 6 and B 2 H 6 produced boron doped p-Si microneedles. The variation of growth rate, diameter, resistivity, impurity concentration and carrier (electron, hole) mobility of these n-Si and p-Si microneeedles were investigated and compared with the variation of dopant gas (PH 3 or B 2 H 6 ) flow, with a fixed flow of Si gas (Si 2 H 6 ). This comparative study shall be helpful while fabricating devices by growing n-Si and p-Si microneedles one above another by multistep (2-step or 3-step) VLS growth. [ABSTRACT FROM AUTHOR]

The measurement of impact force by use of a piezoelectric force transducer or similar device is complicated by: (i) the transducer is mechanically resonant, and the output signal is therefore not necessarily a direct measure of the input force, particularly if the contact time is near to the period of resonance; and (ii) the transducer’s mechanical characteristics, such as mass and stiffness, mean that the transducer itself affects the impact characteristics and force profile. This paper describes an attempt to measure impact force profiles without the use of a separate force transducer. However it has been found that the technique is not suitable due to poor repeatability. [ABSTRACT FROM AUTHOR]

Extensive research on the effect of spark-plasma sintering and free forging on the microstructure, transformation temperature, and superelasticity of Ti-23 at% Nb shape-memory alloys (SMAs) was undertaken. Based on the obtained results, it was found that the specimen showed significant results after deformation than the homogenization step, from which it can be concluded that the deformation has considerable effects on the mechanical properties and shape-memory characteristics of Ti-based SMAs. The microstructure of homogenized and deformed Ti-23 at% Nb SMAs consists of β, α, α′ and ω phases, while the sintered sample shows only β and α phases. Endothermic and exothermic peaks of the austenite ↔ martensite transformation are seen in the homogenized sample, then after being deformed, the exothermic peak disappeared. The highest austenite start and finish temperatures were observed with the deformed sample due to disappearance of TiNb 4 intermetallic compounds and a high percentage of β phase. The ductility of the deformed sample shows the highest value compared with the homogenized sample due the elimination of coarse α precipitates and brittle intermetallic compounds of TiNb 4 , along with the suppression of the brittle ω phase and retaining β matrix. [ABSTRACT FROM AUTHOR]