Metallic alloys' behavior at high temperatures, especially their response to corrosion and formation of protective surface layers, has long been a focus of scientific inquiry. Although certain alloy ...compositions require an initiation period before hot corrosion advances to the propagation stage, no combination of alloys can be considered impervious to hot corrosion indefinitely. The capacity of nickel-based materials to tolerate extreme circumstances such high temperatures, acidity, corrosion, and scratching is highly valued. However, they are unable to satisfy the strict demands of today's high-temperature applications. The durability of thermal barrier coatings (TBCs), which are prone to oxidation, rust, and degradation from sulphates and foreign object damage, has been the subject of recent study. For sophisticated ceramic materials exposed to high temperatures, hot rust degradation poses a considerable challenge. The main objective of this study is to investigate the effects of severe degradation on several advanced ceramic material types and their level of advancement. The purpose of the inquiry is to comprehend the deteriorating processes at the long term working condition, including the function of oxidation and liquid salts. Additionally, we investigate the effects of temperature, environment, and contact duration on the heated weathering behavior of earthenware. Finally, we discuss strategies for mitigating hot corrosion degradation in ceramics, such as protective coatings like new design of TBCs, doping, and composition optimization. This paper aims to offer a thorough understanding of the hot corrosion behavior of ceramics, which is crucial for developing durable materials suitable for high-temperature applications. Additionally, it explores the fabrication of protective coatings and addresses the challenges faced in this regard. The insights gained from this research can contribute to the advancement of resilient ceramic fabrics and the development of effective protective coatings.
Contamination of agricultural land with heavy metal is a serious biological and environmental issue. Such threat can be challenged by exploring the plant symbiotic microbes that can improve plant ...growth through phyto-hormones secretion and chromate chelation. In the current study, chromate resistant rhizospheric Staphylococcus arlettae strain MT4 was isolated from the rhizosphere of Malvestrum tricuspadatum L. The strain showed potential to secrete phytohormones and plant growth promoting secondary metabolites under induced chromate stress, making it a best suitable candidate in chromate stress alleviation. Moreover, the rhizobacterium MT4 significantly promoted the net assimilation and relative growth rate of sunflower grown in the presence of chromate (100 ppm). Chromate stress alleviation strategy of MT4 strain was three-fold. MT4 alleviated chromate stress and promoted the sunflower growth by suppressing the chromate intake by the host, modulating phytohormones and strengthening of the host’s antioxidant system. The improved antioxidant system was confirmed by noticing lower ROS accumulation and improved ROS scavenging, lower peroxidase activity and higher accumulation of phenols and flavonoids.
•Staphylococcus arlettae MT4 significantly promotes net assimilation and relative growth rate of Cr stressed sunflower.•MT4 associated seedlings had reduced uptake and higher reduction of Cr.•Strong antioxidant system of MT4 associated seedlings immuned them to grow healthy under Cr stress.
In modern agricultural practice, heavy metal (HM) contamination is one of the main abiotic stress threatening sustainable agriculture, crop productivity, and disturb natural soil microbiota. ...Different reclamation techniques are used to restore the contaminated site; however, they are either costly or unable to remove contaminant when concentration is very low. In such circumstances, bioremediation is used as a novel technique involving microbes for soil restoration. In the current project,
Aspergillus welwitschiae
(Bk) efficiently endure metal stress (i.e., Cr-VI and As-V in the form of K
2
Cr
2
O
7
and Na
3
AsO
4
) up to 1200 μg/mL and enhanced the production of phytohormones, i.e., 54.83 μg/mL of indole acetic acid (IAA) compared to control 15.56 μg/mL, solubilized inorganic phosphate, and produced stress-related metabolites. The isolate Bk was able to enhance growth of soybean by showing higher root shoot length and fresh/dry weight under stress (
p
<0.05). Besides, the strain strengthened the antioxidant system of the host increasing enzymatic antioxidants, i.e., catalases (CAT) by 1.58 and 1.11 fold, ascorbic acid oxidase (AAO) by 6.75 and 7.94 fold, peroxidase activity (POD) by 1.12 and 1.37 fold, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) by 1.42 and 1.25 fold at 50 μg/mL of chromate and arsenate. Thus, actively scavenging the reactive oxygen species (ROS) produced results in lower ROS accumulation and high ROS scavenging. On the other hand, the isolates cut down Cr and As uptake by approximately 50% at 50 μg/mL from the medium while bio-transforming it, thereby stabilizing it and assisting the host to resume normal growth, thus avoiding phytotoxicity. It is evident from the current study that
A. welwitschiae
may potentially be used as a bioremediating agent for reclamation of Cr- and As-contaminated soil.
Protective coatings for harsh environments are always welcome, but they must overcome profound challenges, including corrosion and wear resistance. The purpose of this study is to look into the ...long-term potentiodynamic polarization measurements and dry tribometric behavior of plasma-sprayed amorphous coatings on AISI 1035 mild steel. To investigate the impact of unique active polarization potentials on the electrochemical studies of the iron-based amorphous layer, which compares favorably to AISI 1035 mild steel, the active potential polarization curve and friction coefficient tests were performed. Scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) analyses were used to investigate the coating's corrosion behavior. Their mechanical (Tribometric tests at higher sliding speeds) and chemical properties (electrochemical potentiodynamic polarization investigations) have also been thoroughly investigated. There is enough validation that these protective coatings can be used in hostile environments. The effects of long-term corrosion for 24 and 48 h were thoroughly examined. Tribometric examinations revealed that amorphous layers are highly resistant under dry conditions, as they offered a very low and stable friction coefficient less than 4 μ with micro Vickers hardness 1140 ± 22.14 HV, which is more than twice as compared to mild steel AISI 1035. The corrosion resistance of coatings in 3.5 wt % NaCl solution displays active transition characteristics of activation, passivation, over passivation, and pitting, as shown by the potentiodynamic polarization curves.
Heavy metals contaminated soil is a serious environmental concern that has a negative impact on agriculture and ecosystem. Economical and efficient ways are needed to address this problem worldwide. ...In this regard, exploration and application of proficient microbial strains that can help the crop plants to thrive in agricultural soils that are greatly contaminated with heavy metals. The present study mainly focused on the effect of IAA producing endophytic fungi Penicillium ruqueforti Thom., on wheat plants cultivated in soil rich in heavy metals (Ni, Cd, Cu, Zn, and Pb). P. ruqueforti has induced great resistance in wheat inoculated plants grown in heavy metal contaminated soil. Application of the isolated strain of P. ruqueforti restricted the transfer of heavy metals from soil to the plants by secreting indole acetic acid (IAA). Furthermore, P. ruqueforti inoculated wheat seedlings watered with waste water had higher plant growth, nutrient uptake and low concentrations of heavy metals in shoot and roots. On the contrary, non-inoculated wheat plants under heavy metal stress had stunted growth with symptoms of chlorosis. From the results, it is concluded that P. ruqueforti inoculation can establish a symbiotic relationship with host plants, which is useful for phytostabilization of heavy metals or in other words helping the host crops to flourish through soil that are highly contaminated with heavy metals.
Drought is a severe environmental constraint, which significantly affects plant growth, productivity, and quality. Plants have developed specific mechanisms that perceive the stress signals and ...respond to external environmental changes via different mitigation strategies. Abscisic acid (ABA), being one of the phytohormones, serves as an important signaling mediator for plants’ adaptive response to a variety of environmental stresses. ABA triggers many physiological processes, including bud dormancy, seed germination, stomatal closure, and transcriptional and post-transcriptional regulation of stress-responsive gene expression. The site of its biosynthesis and action must be clarified to understand the signaling network of ABA. Various studies have documented multiple sites for ABA biosynthesis, their transporter proteins in the plasma membrane, and several components of ABA-dependent signaling pathways, suggesting that the ABA response to external stresses is a complex networking mechanism. Knowing about stress signals and responses will increase our ability to enhance crop stress tolerance through the use of various advanced techniques. This review will elaborate on the ABA biosynthesis, transportation, and signaling pathways at the molecular level in response to drought stress, which will add a new insight for future studies.
This work presents a systematic design of high performance eight element antenna array for a 5G mobile terminal operating at 2.6/3.5 GHz bands. The proposed eight element slot antenna array based on ...unit monopole slot antenna embedded in the metal casing or ground resonates at fundamental mode at 2.6 GHz. The antenna array is developed from four antennas (open-end slot antenna) etched near to the corner edges of the printed circuited board with supported pairs of vertically mounted slot antennas in middle section of the long edge ground plane. This combination of the antenna elements provided pattern diversity and enabled the smartphone in the reception of the signal in a different direction. The impedance bandwidth based on −10 dB return loss criteria cover from 2.4 GHz to 3.6 GHz includes the two allocated bands of (2400 MHz to 2600 MHz) and (3400 MHz to 3600 MHz) for 5G cellular communication systems. The vital MIMO performance measures as envelope correlation coefficient or ECC is less than 0.2 for any two antenna array meeting the required standard of less than 0.5 alongside the mean effective gain or MEG ratio of any two antenna meeting the required standard of less than 3 dB for power balance and optimal diversity performance. As modern smartphone demand desires slim handsets, the after mentioned compact multiple antenna structure can be easily implemented for the future smartphones as it utilizes the conductive sheet or chassis and the middle vertically mounted antenna do not use the additional space of the chassis or ground. The customer hand or human hand effect on the multiple antenna array to mimic the use of mobile phone customer is also studied. The maximum MIMO Channel capacity based on measured result is 34.25bps/Hz and is about 3 times of <inline-formula> <tex-math notation="LaTeX">2\times2 </tex-math></inline-formula> MIMO operations.
A compact, high performance, and novel-shaped ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna with low mutual coupling is presented in this paper. The proposed antenna consists of ...two radiating elements with shared ground plane having an area of 50 x 30 mm 2 . F-shaped stubs are introduced in the shared ground plane of the proposed antenna to produce high isolation between the MIMO antenna elements. The designed MIMO antenna has very low mutual coupling of (S 21 <; -20 dB), low envelop correlation coefficient (ECC <; 0.04), high diversity gain (DG > 7.4 dB), high multiplexing efficiency (η Mux > -3.5), and high peak gain over the entire UWB frequencies. The antenna performance is studied in terms of S-Parameters, radiation properties, peak gain, diversity gain, envelop correlation coefficient, and multiplexing efficiency. A good agreement between the simulated and measured results is observed.
This article proposes an efficient and complete wireless power transfer (WPT) system (WPTS) for multipurpose biomedical implants. The WPTS is composed of a self-diplexing implantable antenna, ...efficient rectifier, and WPT transmitter (WPT Tx). The proposed system is capable of simultaneously transmitting recorded data and recharging the batteries of the devices (so as to elongate the implant life). The WPT Tx occupies dimensions of <inline-formula> <tex-math notation="LaTeX">50 \times 50 \times 1.6 </tex-math></inline-formula> mm 3 and is optimized to effectively transfer power at 1470 MHz to a 55-mm deep implantable device. An efficient and compact (<inline-formula> <tex-math notation="LaTeX">3.4 \times 6.7 </tex-math></inline-formula> mm 2 ) rectifier is used at 1470 MHz to convert the harvested RF power into a useful direct current (dc) power. The proposed rectifier circuit exhibits a high conversion efficiency of 50% even at an input power of −14 dBm and maximum efficiency of 76.1% at 2 dBm. The proposed self-diplexing implantable antenna occupies small dimensions (9.4 mm 3 ) and operates at 915 and 1470 MHz by exciting ports 1 and 2, respectively. The biotelemetry operation is performed using a 915 MHz band (port 1), and the rectifier circuit is connected to port 2 (1470 MHz) to perform wireless powering. The simulated results are validated by examining the individual elements (WPT Tx, rectifier, and self-diplexing antenna) and overall WPTS in a saline solution and minced pork. The results prove that the proposed scheme is suitable for biotelemetry and wireless powering of biomedical implants.
A novel dual-port, dual-band self-duplexing implan- table antenna for head implants is presented in this article. It operates at 915 MHz Industrial, Scientific, and Medical (ISM) band (when Port 1 is ...active) and 1420 MHz Wireless Medical Telemetry Service (WMTS) band (when Port2 is active). The proposed antenna is kept inside a flat device and simulated in a human head model. The miniaturization of the proposed antenna is achieved using a high dielectric substrate, shorted pins, and multiple capacitive slots. Consequently, it occupies a compact volume of <inline-formula> <tex-math notation="LaTeX">7.13 \times 8.9 \times 0.13= 8.24 </tex-math></inline-formula> mm 3. The coupling between both radiators is enhanced by printing it on a thin substrate and placing vias between them. As a result, an isolation level better than 31.4 dB is achieved. It has peak realized gains of −18.94 and −17.06 dBi at 915 and 1420 MHz, respectively. The link budget analysis and specific absorption rate (SAR) are performed, showing promising results. The proposed concept is practically validated by measuring its performance inside the minced pork meat. Furthermore, the simultaneous transmit and receive concept is practically verified with the aid of software-defined radio (SDR). The main advantages of this antenna are its compact size, low coupling level, independently controllable bands, and simultaneous transmission and reception of signals without using a multiplexer circuit.
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