Found 197 results
Communication
08 January 2025Development of Eco-Friendly Composites Using Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Diss Fibers (Ampelodesmos Mauritanicus)
In response to the growing environmental threats and pollution linked to synthetic plastics, current scientific inquiry is prioritizing the advancement of biodegradable materials. In this context, this study investigates the possibility of developing fully biodegradable materials using plant fibers extracted from the Diss plant (Ampelodesmos mauritanicus) as reinforcement in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)-based biocomposites. The biocomposites were prepared by melt blending in the following weight ratio: PHBV/Diss fibers 80/20. The chemical structure of Diss fibers was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray fluorescence spectrometry (XRF). The impact of Diss fibers on the mechanical properties of biocomposites has also been investigated in comparison to neat PHBV. FTIR and XRF analyses identified cellulose, hemicellulose, and lignin as the main components of Diss fibers. On the other hand, the results showed a significant enhancement of Young’s modulus (⁓21%) of PHBV/DF biocomposites in comparison to neat PHBV due to a better dispersion of the fibers in the matrix, as confirmed by atomic force microscopy (AFM) images.
Article
07 January 2025Trace DNA Recovery: Insights from Dubai Police Casework
Trace DNA represents a critical form of forensic evidence, frequently recovered from a wide variety of touched or used items. Despite its evidentiary value, trace DNA analysis poses significant challenges due to the minute quantities of DNA involved, as well as the influence of factors such as surface type, collection methods, and environmental exposure. This study systematically examines the success rates and characteristics of trace DNA profiles recovered from six-item categories—tools, stolen items, wearable items, packaging materials, vehicles, and touched items—processed between 2021 and 2023 by the Biology and DNA Section of the Dubai Police Force. A total of 6277 cases were analyzed, encompassing a range of crimes, including homicide, suicide, missing persons, paternity disputes, and burglary. The results demonstrated an overall trace DNA success rate of 64%, with wearable items yielding the highest success rate at 76% and packaging materials yielding the lowest at 54%. Detailed analysis of positive DNA trace samples revealed significant variability in DNA profile types across item categories. Wearable items and touched items predominantly yielded full single (FS) DNA profiles, reflecting their reliability as sources of singular and high-quality DNA. Conversely, stolen items and packaging materials showed a greater prevalence of full mixed (FM) DNA profiles, highlighting their association with complex mixtures due to handling by multiple contributors. Tools and vehicles, meanwhile, exhibited higher rates of partial profiles, presenting unique challenges related to surface irregularities and environmental factors. This study emphasizes the importance of tailoring forensic strategies to item-specific characteristics, as well as the need for systematic mechanisms to categorize trace samples. Addressing operational challenges such as manual sorting and leveraging automation or AI-based systems can further streamline trace DNA analysis. The findings also underscore the importance of data sharing and standardization across forensic laboratories to enhance trace DNA recovery protocols and improve reliability in forensic investigations. Future research should focus on the effects of material properties, environmental exposure, and collection techniques on DNA retention, advancing the field of trace DNA profiling and its applications in forensic science.
Article
06 January 2025A Bounded-Function-Based Scheme for Finite-Time Stabilization of a NWMR with Input Constraints
This paper addresses the finite-time stabilization problem for a nonholonomic wheeled mobile robot (NWMR) with input constraints. By utilizing the hyperbolic tangent function tanh(·), bounded finite-time stabilization controllers are developed. In addition, an explicit upper-bound estimate for the closed-loop settling time is given, and the level of input constraints is characterized by parameters that depend on the actuator’s capacity. A thorough finite-time stability analysis is carried out using appropriate Lyapunov functions. For a compact set contained in the domain of attraction, a guideline is presented to clarify how to construct it. Finally, simulation results show the effectiveness of the developed controllers.
Review
02 January 2025Cell-Autonomous and Non-Cell-Autonomous Antiviral Immunity via siRNA-Directed RNAi in Drosophila melanogaster
In Drosophila melanogaster, the siRNA-directed RNAi pathway provides crucial antiviral defenses. Cell-autonomously, Dicer-2 (Dcr-2) recognizes and cleaves viral dsRNA into siRNAs, which are incorporated into the RNA-induced silencing complex (RISC). Argonaute 2 (Ago2) then targets and cleaves viral RNA, preventing replication. Non-cell-autonomously, infected hemocytes secrete exosomes containing viral siRNAs, spreading antiviral signals to other cells. Additionally, tunneling nanotubes can transfer RNAi components between neighboring cells, further enhancing systemic immunity. These findings highlight the sophisticated antiviral strategies in Drosophila, offering insights for broader antiviral research.
Article
31 December 2024Porous 430L Stainless Steel as a Support Layer for Planar
Solid Oxide Cells: Effect of Porosity on Mechanical Properties
Porous 430L stainless steel
components fabricated via tape casting underwent mechanical testing for
potential in-vehicle application as mechanical supports of solid oxide cells.
Tests included three-point bending up to 5% strain to assess flexural strength,
yield strength, Young’s modulus, indentation hardness, and microstructural
characterization. This study aimed to establish the relationship between pore
former size and volume fraction and the resulting yield strength. It also
compared sintered material without pore former, focusing on the influence of a
wide range of porosity of up to 46.5%. The materials exhibited an inverse
relationship for Young’s modulus, hardness and yield strength as a function of
porosity. The lowest flexural yield strength obtained was approximately 120 MPa
at the highest porosity of 46.5%, meeting the requirement of 59 MPa for the
bipolar plates of existing proton-exchange membrane fuel cells.
Perspective
31 December 2024
Offshore Renewable Energy Advance
Offshore renewable energy generation has become an important means to address the energy crisis and climate change, which has gained widespread attention in recent years. This article presents classic domestic and international cases that introduce the development and industrial transformation of generation technologies for offshore wind, offshore photovoltaics, ocean wave energy, tidal energy and temperature difference energy. Offshore power generation projects face challenges in design, safety, long-term operation and economic feasibility. Offshore renewable energy generation is gradually moving towards industrialization, and is expected to become a key component of global energy supply in the future with technological advancements and policy support, providing strong support for tackling climate change and achieving sustainable development goals.
Article
27 December 2024Effect of Magnesium Aluminum Silicate Addition on the Ablation Resistance of BN Matrix Ceramics
Ablation resistance is a critical factor in evaluating the performance of BN-based ceramic composites under extreme service conditions. This study investigates the ablation behavior and underlying mechanisms of BN-MAS wave-transparent ceramic composites with varying magnesium aluminum silicate (MAS) content through oxyacetylene torch tests. The results reveal that increasing the MAS content reduces the mass ablation rate from 0.0298 g/s to 0.0176 g/s and the linear ablation rate from 0.149 mm/s to 0.112 mm/s. The incorporation of MAS into h-BN ceramics significantly lowers the surface ablation temperature, primarily due to the evaporation of B2O3 (g) and MAS ceramics. Cross-sectional analysis of the ablated composites indicates the presence of micro- and macro-spallation in the ablation center. The primary ablation products are magnesium-aluminum borosilicate glass and mullite. Key ablation mechanisms include the oxidation of h-BN under flame exposure, the erosion of viscous oxidation products, and the physical degradation of the matrix caused by the high-velocity gas flow.
Article
17 December 2024Upcycling of Waste Poly(ethylene terephthalate) into 2,4-Pyridine Dicarboxylic Acid by a Tandem Chemo-Microbial Process
This study presents a chemo-microbial cascade process for the upcycling of waste poly(ethylene terephthalate) (PET) into valuable compound 2,4-pyridine dicarboxylic acid (2,4-PDCA). Initially, waste PET undergoes efficient hydrolysis to terephthalic acid (TPA) with a high yield of 92.36%, catalyzed by p-toluenesulfonic acid (PTSA). The acid catalyst exhibits excellent reusability, maintaining activity over five cycles. Subsequently, a one-pot, two-step whole-cell conversion system utilizing genetically modified Escherichia coli strains (E. coli PCA and E. coli 2,4-PDCA) converts the generated TPA into 2,4-PDCA. By integrating the PET hydrolysis module with the 2,4-PDCA biosynthesis module, the study achieves an impressive overall efficiency of 94.01% in converting challenging PET waste into valuable 2,4-PDCA. Our research presents a rational design strategy for PET upcycling and 2,4-PDCA synthesis methods. This research provides a systematic approach to PET upcycling, demonstrating its feasibility and potential for industrial application.
Article
16 December 2024Price and Output Response of Major Food Grains of Nadia District of West Bengal
The price and output response of food crops is a critical area in agricultural economics as this interaction refers to how the quantity of food grains supplied responds to changes in market prices. This research investigates the surplus ratios and price elasticities for rice, lentil, and gram in the Nadia district of West Bengal. Two hundred farmers were interviewed in different villages of the district and information was collected regarding socio-economics, marketed surplus and, selling price, etc. Further, elasticity and a modified version of the Raj Krishna model have been employed. The findings reveal that for rice, the ratios of gross, net marketed, and marketable surplus are 69.59%, 55.46%, and 16.27%, respectively. The gross marketed surplus ratio decreases with a reduction in farm size, while net marketed and marketable surpluses increase as farm size expands. For lentils, the gross and net marketed surplus ratios are recorded at 66.64% and 65.57%, with an average marketable surplus of 35.30%. Marginal gram farmers have a gross marketed surplus ratio of 80.33%, slightly lower than the overall average of 81.12%, whereas larger farms exceed this average, with ratios of 82.19% and 83.18%. Output elasticities for rice are positive and exceed unity for both marginal and large farms, at 1.03 and 1.45, respectively, though slightly below unity at 0.85 for small farms. The average elasticity for rice across all farm sizes is 1.12. Lentil output elasticities are also positive and greater than unity for marginal and large farms (1.00 and 1.07, respectively) but fall below unity at 0.78 for medium farms, with an overall average of 0.91. The output elasticities for gram remain consistently positive and above unity across all farm sizes, averaging 1.09.
Article
16 December 2024Exploring the Values of Sustainability and the Cost of Going Green: A Case of Building Research Establishment Environmental Assessment Method (BREEAM)
Despite the expansion of BREEAM and the benefits of adopting sustainable building practices, there are concerns that the cost of going green may outweigh the benefits. Whilst previous studies have not provided adequate clarity in this regard, there is consensus among scholars that BREEAM provides indirect benefits that can be considered as added value. This paper aims to investigate the potential cost implication and benefits of sustainable building practices from the lens of the Building Research Establishment Environmental Assessment Method (BREEAM) in the UK. Adopting survey research strategy, questionnaires, and interviews with 34 construction industry professionals in Southeast England were conducted to investigate their perceptions of BREEAM, the extra value it contributes to projects, and the possible limitations hindering its wider adoption. Findings show that while there is an upfront investment associated with achieving BREEAM certification, the benefits of such certification include added values such as improved environmental performance, increased market appeal, improved indoor air quality, reduced carbon emissions, and lower operational costs. This study validates the need to encourage wider adoption of sustainable building practices and promote the use of the BREEAM methodology in the UK. This research provides a foundation for future research and development in this area, with the goal of reducing carbon emissions and promoting sustainable development.
