Search Results (295)

Reclaimed fields have a low soil fertility and low productivity compared to conventional arable land, necessitating research on productivity enhancement. The rice–frog co-culture model is an ecologically intensive practice that combines biodiversity objectives with agricultural production needs, offering high ecological and economic value. However, there is a lack of research on this model that has focused on factors other than soil nutrient levels. The present study evaluated the rice–frog co-culture model in a reclaimed paddy field across three experimental plots with varying frog stocking densities: a rice monoculture (CG), low-density co-culture (LRF), and high-density co-culture (HRF). We investigated the effects of the frog density on greenhouse gas emissions throughout the rice growth. The rice–frog co-culture model significantly reduced methane (CH₄) emissions, with fluxes highest in the CG plot, followed by the LRF and then HRF plots. This reduction was achieved by altering the soil pH, the cation exchange capacity, the mcrA gene abundance, and the mcrA/pmoA gene abundance ratio. However, there was a contrasting nitrous oxide (N₂O) emission pattern. The co-culture model actually increased N₂O emissions, with fluxes being highest in the HRF plots, followed by the LRF and then CG plots. The correlation analysis identified the soil nosZ gene abundance, redox potential, urease activity, nirS gene abundance, and ratio of the combined nirK and nirS abundance to the nosZ abundance as key factors associated with N₂O emissions. While the co-cultivation model increased N₂O emissions, it also significantly reduced CH₄ emissions. Overall, the rice–frog co-culture model, especially at a high density, offers a favorable sustainable agricultural production model. Full article

The advancement of Internet of Things (IoT) technology has enabled battery-powered devices to be deployed across a wide range of applications; however, it also introduces challenges such as high energy consumption and security vulnerabilities. To address these issues, adiabatic logic circuits offer a promising solution for achieving energy efficiency and enhancing the security of IoT devices. Adiabatic logic circuits are well suited for energy harvesting systems, especially in applications such as sensor nodes, RFID tags, and other IoT implementations. In these systems, the harvested bipolar sinusoidal RF power is directly used as the power supply for the adiabatic logic circuit. However, adiabatic circuits require a peak detector to provide bulk biasing for pMOS transistors. To meet this requirement, a diode-connected MOS transistor-based voltage doubler circuit is used to convert the sinusoidal input into a usable DC signal. In this paper, we propose a novel adiabatic logic design that maintains low power consumption while optimizing energy and current fluctuations across various input transitions. By ensuring uniform and complementary current flow in each transition within the logic circuit’s functional blocks, the design reduces energy variation and enhances resistance against power analysis attacks. Evaluation under different clock frequencies and load capacitances demonstrates that the proposed adiabatic logic circuit exhibits lower fluctuation and improved security, particularly at load capacitances of 50 fF and 100 fF. The results show that the proposed circuit achieves lower power dissipation compared to conventional designs. As an application example, we implemented an ultrasonic transmitter circuit within a LoRaWAN network at the end-node sensor level, which serves as both a communication protocol and system architecture for long-range communication systems. Full article

Wetlands are the most important natural sources of methane. Studies on the distribution and diversity of methanotrophs, especially in tropical wetlands, are limited. The studies on wetland methanotrophs help bridge the gap in the literature for understanding the community structure of methanotrophs in tropical wetlands. Our present study documents the methanotroph diversity from various wetland habitats across Western India. Samples from various sites, such as freshwater ponds, lake sediments, mangroves, etc., located in Western India, were collected and enriched for methanotroph isolation. An established protocol for the isolation of methanotrophs from Indian rice fields, involving serial dilution and long-term incubations, was slightly modified and used. Obtaining entirely pure cultures of methanotrophs is a labor-intensive and technically challenging process. Hence, for primary level characterization, ‘methanotroph monocultures’, which have a single methanotroph culture with minimal contamination, were established. Twenty monocultures and eight pure cultures of methanotrophs were obtained in this study. The pmoA gene has been used for the phylogenetic characterization of methanotrophs for the last 25 years. Monocultures were from seven genera: the Methylomonas, Methylocystis, Methylosinus, Methylocaldum, Methylocucumis, Methylomagnum, and Methylolobus genera. Eight pure cultures were obtained, which were strains of Methylomonas koyamae, Methylosinus sporium, and Methylolobus aquaticus. A maximum number of cultures belonged to the Type I genus Methylomonas and to the Type II genus Methylocystis. Thus, the cultivation-based community studies of methanotrophs from wetland habitats in India expanded the current knowledge about the methanotroph diversity in such regions. Additionally, the cultivation approach helped us obtain new methanotrophs from this previously unexplored habitat, which can be used for further biotechnological and environmental applications. The isolated monocultures can either be used as MMCs (mixed methanotroph consortia) for environmental applications or further purified and used as pure cultures. Full article

Background: In addition to the well-known vitamin D metabolites 25(OH)D and 1,25(OH)₂D, the catabolite 24,25(OH)₂D may also reflect vitamin D status and influence biological and skeletal processes. However, the effects of UVR-induced synthesis on 24,25(OH)₂D levels and the 25-VMR (24,25(OH)₂D3:25(OH)D3 ratio) remain unclear. Objectives: We aimed to assess how a single standardised UVR dose influences the production of 25(OH)D3, 24,25(OH)₂D3, 1,25(OH)₂D3 and 25-VMR, with a comparison between younger and older adults being conducted to explore potential age-related differences in vitamin D metabolism. Methods: A total of 11 young (18–40 years; 7M, 4F) and 10 older (65–89 years; 6M, 4F) skin type I-III volunteers received a single sub-erythemal dose of solar simulated UVR (SSR) (95% UVA: 320–400 nm, 5% UVB: 290–320 nm, 1.3 standard erythemal dose) during winter time in the UK (vitamin D trough season), exposing approximately 35% of the body surface area. The Blood was assayed for 25(OH)D3, 24,25(OH)₂D3 and 1,25(OH)₂D3 using LC-MS/MS at baseline, 24 h and 7 days following UVR exposure. Results: There was a significant increase in 25(OH)D3 from baseline (44 ± 22 nmoL/L) to 24 h post-UVR (48 ± 22 nmoL/L) in the combined age group (p = 0.044), but no significant differences were found in 24,25(OH)₂D3 in the combined group, or between young and older volunteers for both metabolites. 1,25(OH)₂D3 concentrations were higher in young groups (163 ± 60 pmoL/L) than in older (105 ± 38 pmoL/L) groups at 7 days post-UVR (p = 0.044). The 25-VMR decreased from baseline (9 ± 3) to 24 h post-UVR (7.5 ± 2.1) in the combined group (p = 0.003). Conclusions: Our data suggest that a single sub-erythemal UVR challenge does not influence 24,25(OH)₂D3 concentration in younger and older adults at 24 h and 7 days post-UVR and that the significant difference seen in the 25-VMR between baseline and 24 h post-UVR is due to the increase in 25(OH)D3 concentration post-UVR. This is in line with vitamin D oral supplementation studies, and indicates that low doses of UVR trigger the metabolic pathway, without affecting the catabolic pathway. Full article

This paper introduces a high-efficiency buck converter designed for a wide load range, targeting low-power applications in medical devices, smart homes, wearables, IoT, and technology utilizing WiFi and Bluetooth. To achieve high efficiency across varying loads, the proposed converter employs a low-power adaptive on-time (AOT) controller that ensures output voltage stability and seamless mode transitions. An adaptive comparator (ACP) with variable output impedance is introduced, offering a variable DC gain and bandwidth to be suitable for different load conditions. A negative-level shifter (NLS) circuit, with its swing ranging from −0.5 V to the battery voltage (V_BAT), is proposed to control the smaller power p-MOS transistors. By using an NLS, the chip area, which is mostly occupied by power CMOS transistors, is reduced while the power efficiency is improved, particularly under a heavy load. A status time detector (STD) block which provides control signals to the ACP and NLS for optimized power consumption is added to identify load conditions (heavy, light, ultra-light). By employing a 180 nm CMOS technology, the active chip area occupies about 0.31 mm². With an input voltage range of 2.8–3.3 V, the controller’s current consumption ranges from 1.2 μA to 16 μA, corresponding to the output load current varying from 12 μA to 120 mA. Although the output load can vary, the output voltage is regulated at 1.2 V with a ripple between 3 and 12 mV. The proposed design achieves a peak efficiency of 96.2% under a heavy load with a switching frequency of 1.3 MHz. Full article

Solar photovoltaic (PV) panels are the best solution to reduce greenhouse gas emissions by fossil fuel combustion, with global capability now exceeding 714 GW due to rapid technological advances in solar panels (SPs). However, SPs’ efficiency and lifespan remain limited due to the absence of advanced fault-detection systems, and they are prone to short circuits (SC), open circuits (OC), and power degradation. Therefore, this large-scale production requires reliable, real-time fault diagnosis to maintain panel performance. However, traditional diagnostic methods implemented using MPPT, neural networks, or microcontroller-based systems often rely on complex computational algorithms and are not cost-effective. So, this paper proposes a diagnostic system composed of six functional blocks to address this issue. The proposed system was initially verified using an Intel DE-10 Lite FPGA board. Once its functionality was confirmed, an ASIC design was proposed for mass production, offering a significantly lower implementation cost and reduced hardware complexity than prior methods. Different circuit designs were developed for each of the six blocks. All designs were created using Cadence software and TSMC 180 nm technology files. The basic components used in these designs include PMOS transistors with 300 nm channel length and 2 µm width, NMOS transistors with 350 nm channel length and 2 µm width, as well as resistors and capacitors. Differential amplifiers with a gain of 40 dB were used for voltage and current sensing from the SP. The chip activation signal generator circuit was designed with an adjustable frequency and generated 120 MHz and 100 MHz signals in this work. The decision-making block, Logic Driver Circuit, was innovatively implemented using a reduced number of transistors. A custom memory block with a reset switch was also implemented to store the fault value detected at the SP. Finally, the proposed ASIC was implemented for fabrication, which is highly cost-effective in mass production and does not require complex computational stages. Full article

A polyoxometalate-based metal–organic complex with the ability to treat pollutants in water was obtained under hydrothermal conditions, namely [Ni(H₂L)(HL)₂](PMo₁₂O₄₀)·3H₃O·4H₂O (1) (H₂L = 4,4′-(1H,1′H-[2,2′-biimidazole]-1,1′-diyl)dibenzoicacid). Structural analysis reveals that the [Ni(H₂L)(HL)₂] units are interconnected into a 2D layer via hydrogen bonds between adjacent carboxyl groups and water molecules of crystallization. [PMo₁₂O₄₀]³⁻ anions are embedded within the larger pores of the layer and are connected to the adjacent layers through hydrogen bonds, ultimately expanding the structure into a 3D supramolecular architecture. The intermolecular interactions were studied via Hirshfeld surface (HS) analysis. Electrochemical performance tests reveal that 1 exhibits electrocatalytic activity toward the oxidation and reduction of diverse pollutants in water, including NO₂⁻, Cr(VI), BrO₃⁻, Fe(III), and ascorbic acid (AA). Additionally, it can also serve as an amperometric sensor for the detection of BrO₃⁻ and Cr(VI). Photocatalytic studies reveal that compound 1 functions as a bifunctional photocatalyst, which not only achieves efficient degradation of organic dyes but also demonstrates remarkable reduction efficiency for toxic Cr(VI). Compound 1 demonstrates significant potential for practical water remediation applications. Full article

Low-pass filters with bandwidths larger than several GHz are required in many applications, such as anti-aliasing filters in high-speed ADCs and pulse-shaping filters in high-speed DACs. In highly integrated applications, low area occupation and power consumption are key specifications, so inductor-less implementations are to be preferred. Furthermore, full CMOS implementations provide an advantage in terms of technology availability and cost. In this paper, we present an inductor-less CMOS biquad stage based on the super source follower topology that provides an 8 GHz cutoff frequency and a low power consumption of 0.42 mW per pole, showing remarkable performance also in terms of bandwidth and dynamic range. The availability of two separate current sources allows independent tuning of natural frequency and quality factor. The stage can be implemented in two complementary ways, exploiting NMOS and PMOS input devices, respectively, thus simplifying cascadability. The two complementary biquads have been implemented in the STMicroelectronics FDSOI 28 nm CMOS process and extensively simulated and provide stable performance under PVT variations and mismatches. The area occupation is about 387.5 μm² per biquad, one of the lowest in the literature. The figures-of-merit are remarkable, as the filters achieve excellent power efficiency, very low area occupation, and good dynamic range. Full article

Conventional operational amplifier designs often experience parameter performance issues during the transition between complementary input differential stages, which restricts the full rail-to-rail common mode voltage swing. This paper presents an innovative charge pump architecture featuring a feedback supply selector that optimizes the transition performance. The proposed approach employs a switched-capacitor technique to boost the supply voltage by 1.5 V relative to the input voltage, thereby enabling the use of a single pMOS differential input stage. The novel supply selector dynamically chooses the maximum available voltage between the external supply and the boosted output, ensuring efficient transistor switching and improved biasing. Schematic-level and post-layout simulations in a 250 nm CMOS process validate the design under varied load currents, supply voltages, temperatures, and process corners. Results show a significant reduction in output voltage ripple, with a maximum value of 48 mV achieved post-layout, and enhanced overall efficiency, even under higher load currents. This architecture provides a robust and scalable solution for advanced operational amplifiers, particularly in fields where high performance and stability are critical. Full article

This paper explores the transition from traditional Project Management Offices (PMOs) to Value Delivery Offices (VDOs), marking a shift from a process-centric to a value-centric approach in project management. Utilizing a mixed-methods research approach, the study combines quantitative data analysis with qualitative interviews and case studies from various industries. This study provides clear insights into the benefits and strategic impacts of adopting VDOs. Key findings include the pivotal role of change management in facilitating this transition and the introduction of the Value Delivery Maturity Model (VDMM) to assess value delivery progression. The paper discusses practical implications for organizations, recommends strategies for effective implementation and management of VDOs, and identifies potential challenges and solutions in the transition process. This research contributes to the evolving field of project management by highlighting the significance of value-centric approaches in contemporary business environments. Full article

The implementation of ambidextrous innovation in project organizations within the cultures of the Global South, such as Saudi Arabia, is a significant problem. Organizational culture is positioned as a key factor that can help project organizations in cultures such as Saudi Arabia to implement ambidexterity as a key innovation framework. However, knowledge of ambidextrous innovations in such an important cultural and organizational context is highly limited. Thus, the aim of the present research is to explore key cultural aspects and themes based on action and a grounded theory research approach that can help organizations employ projects as a key work structure to implement ambidextrous innovations in project management offices (PMOs) in Saudi Arabia. To achieve this aim, the current study employed in-depth semi-structured interviews with 36 participants. The results, employing open coding procedures as a tool of data analysis using the NVivo 14.0 software package, revealed 62 key cultural aspects that can be critical in implementing the innovation of ambidexterity. To further validate and triangulate the findings, inter-rater reliability was undertaken with the help of two experts, and two sessions of focus group discussions were also conducted. The first session of the focus group helped us critically evaluate and filter the cultural aspects, resulting in the final 56 key cultural aspects. The second focus group session was undertaken with participants with the aim of grouping aspects into theoretical themes, which resulted in 10 themes. The research is novel in that it addresses both project organizations and the culture of the Global South, including Saudi Arabia. Empirical research needs to be conducted to predict and achieve other key outcomes. Full article

Wireless power transfer using beamforming technology has recently gained significant attention for sensor networks and embedded systems. This technology uses array antennas and mid-range RF power (15–20 dBm) rectifiers for efficient power delivery to sensors. Despite its potential, research on mid-range RF power CMOS rectifiers remains limited. Addressing this gap, we propose a high-efficiency pMOS-based rectifier employing a body-biasing technique—a proven method for enhancing device performance—specifically designed for wideband and mid-range RF power RF applications. Conventional rectifiers often depend on precise input impedance matching to achieve high power conversion efficiency (PCE), which restricts bandwidth and limits practicality in dynamic environments. To overcome these challenges, the proposed design integrates a modified matching network, combined with dynamic body-biasing, which lowers the pMOS threshold voltage and minimizes power losses. Simulations reveal a peak PCE of 60.5%, with efficiency exceeding 50% across a broad frequency range up to 2.5 GHz—significantly outperforming traditional designs. Unlike conventional impedance-matching solutions, this rectifier maintains robust performance under input mismatches, making it well-suited for beamforming-based WPT systems. This study highlights the potential of integrating body-biasing with advanced matching networks for efficient wideband rectifiers. Full article

This paper proposes a monolithic electrostatic discharge/electrical overstress (ESD/EOS) co-protection device featuring gradual triggering by silicon-controlled rectifier (SCR) and metal–oxide semiconductor (MOS) structures, demonstrating enhanced voltage clamping and current-conducting capabilities. Compared with conventional PMOS-triggered SCR (PMOS-SCR) for ESD protection, the proposed dual-PMOS-triggered SCR (DPMOS-SCR) architecture within a compact area achieves monolithic ESD/EOS protection performance due to the strategic semiconductor structures integration. ESD measurement results show that the snapback voltage of the designed DPMOS-SCR with the width of 170 μm is approximately 2.5 V, the failure current (I_t2) is up to 4.5 A, and both the simulation and measurement results demonstrate that the designed DPMOS-SCR is helpful for reducing the leakage current and accelerating the response time. By embedding an additional p-type well in the DPMOS-SCR, the optimized DPMOS-SCR (ODPMOS-SCR) presents a higher breakdown voltage, trigger voltage, and holding voltage while keeping a similar I_t2. The EOS current-conducting ability measured by a surge test system indicates the peak surge current is up to 3.7 A, demonstrating superior monolithic ESD/EOS protection performance. As a result, the designed DPMOS-SCR and ODPMOS-SCR structures achieve high-voltage ESD/EOS co-protection with high efficiency in a small chip area, providing a chip-scale solution for improving the reliability of high-voltage ICs. Full article

This study is based on the strategies of composite and element doping. Herein, P-MoS₂/rGO materials were synthesized using a solvent-assisted hydrothermal method. The MoS₂ nanosheets were uniformly and vertically grown on rGO; meanwhile, the optimized structure of MoS₂ was achieved by P doping, resulting in improved catalytic performance and structural stability. Under alkaline conditions, the P-MoS₂/rGO catalyst exhibits good electrocatalytic activity, demonstrating a Tafel slope of 70.7 mV dec⁻¹ and an overpotential of 172.8 mV at 10 mA/cm². Notably, even after 3000 consecutive LSV tests, the curves still show a high degree of overlap, indicating exceptional stability. Full article

Addressing the pressing issue of global warming, sustainable rice cultivation strategies are crucial. Milk vetch (MV), a common green manure in paddies, has been shown to increase CH₄ emissions, necessitating effective mitigation. This two-year field experiment assessed the impact of applying calcium peroxide (CaO₂), widely used in wastewater treatment and soil remediation due to its oxygen-releasing properties, on CH₄ emissions in conventional paddy fields (chemical fertilizer-only) and MV-incorporated fields. The results revealed that in conventional paddy fields, CaO₂ application significantly reduced the average CH₄ emissions by 19% without affecting rice yield. Compared with chemical fertilizer alone, MV incorporation increased the average rice yield by 12% but significantly elevated CH₄ emissions. However, in paddy fields with MV incorporation, CaO₂ application significantly reduced CH₄ emissions by 19% while preserving the yield benefits of MV. Soil analyses indicated that MV incorporation led to increased soil carbon content and increased mcrA and pmoA gene copy numbers, with elevated mcrA gene copy numbers being primarily responsible for the promoted CH₄ emissions. CaO₂ application improved the soil redox potential, reducing mcrA gene copies and consequently mitigating CH₄ emissions. Overall, CaO₂ application can contribute to global efforts to reduce CH₄ emissions while supporting rice productivity. Full article