Hasil untuk "Chemical industries"

L. Salonen, Manuel Ellermann, F. Diederich

A. Funke, F. Ziegler

Joseph B. Binder, Ronald T. Raines

V. L. Campo, D. Kawano, D. Silva et al.

Xuebing Zhao, Lihua Zhang, De‐hua Liu

A. Ashori

R. E. Kirk, D. Othmer

A. Hoffman

Andrew A. King, M. Lenox

Charles M. Cai, Taiying Zhang, R. Kumar et al.

BAI Zongwei, ZHAO Haoqing, WANG Xiaoxuan, WANG Yijia, CHEN Yamei, CHEN Geng, ZHANG Zuohui, ZHAO Lichao

Cinnamon essential oil, a mixture of volatile secondary metabolites from Cinnamomum spp., is widely utilized in the food and pharmaceutical industries due to its distinctive aroma and bioactivities. However, its chemical composition is highly influenced by various factors such as species, environment, and plant part, and the intrinsic relationship between the chemical composition of cinnamon essential oil and its functional properties remain inadequately clarified. This review provides a systematic overview of recent advances in understanding the chemical composition and functional activities of cinnamon essential oil. It first summarizes the key factors—genetic background, cultivation conditions, and plant part—that determine the chemical profile. It then discusses the contribution of major constituents (e.g., trans-cinnamaldehyde and 2-methoxycinnamaldehyde) to main bioactivities such as antimicrobial and antioxidant properties. Finally, the review synthesizes the interconnections among three dimensions: “raw material source (species, environment, and plant part), chemical composition (key components and their concentrations), and functional properties (e.g., antimicrobial and antioxidant activities)”. This review aims to provide a theoretical foundation for enhancing the quality control of cinnamon essential oil and enabling its standardized application.

Nicole de M. Vianna, Gabriel Albagli, Adejanildo da S. Pereira et al.

The Symbiotic Culture of Bacteria and Yeast (SCOBY) is a cellulose-based biofilm resulting from the fermentation of sweetened tea by a microbial consortium of acetic acid bacteria and yeasts. This study applies the <i>Methodi Ordinatio</i> technique to systematically identify, rank, and analyze the most relevant scientific publications on the applications of SCOBY. A comprehensive search in SCOPUS and Web of Science yielded 179 articles, after manual filtration. The InOrdinatio index, which combines citation count, publication year, and journal impact factor, was used for ranking to select a representative sample of the most important contributions (117 articles). The highest-ranked article scored 128.9, and the lowest 42.6. China led in scientific output (14.01%), followed by India (11.46%), the UK and USA (5.10% each), and Brazil (4.46%). The International Journal of Biological Macromolecules was the most frequently used journal for publications in this field. “Bacterial cellulose” was the most cited keyword (61 times), followed by “kombucha” (41) and “fermentation” (29). A consistent rise in publications has been observed over the past five years. Four main application areas were identified: bacterial cellulose (BC) (38%), biosustainable materials (28%), biomedical (17%), and food-related uses (17%). Most of the studies related to BC production (52%) searched for alternative substrates, and 18% focused on the isolation and identification of the most productive microorganisms within SCOBY. For biomedical applications, a unifying theme is the development of SCOBY-based materials with intrinsic antibacterial properties. These findings emphasize SCOBY’s emerging role in sustainable innovation and circular economic frameworks.

Doniyarov Nodirjon, Vafoev Akhtam

The Karychsay deposit in Uzbekistan is an important site for the extraction and beneficiation of various types of mineral resources, especially leucocratic granites. Leucocratic granites are important igneous rocks that contain significant amounts of feldspar and quartz and dark colored minerals in smaller quantities. Granites of this nature have found widespread use in important industries such as construction, industry, in the production of cladding materials and for the production of a number of other economically important metals. The paper considers the necessary properties of leucocratic granites such as durability, strength and attractiveness these rock formations which are essential items in the growing demand for high quality materials for construction and architectural design. The Karichsay deposit in Uzbekistan is one of the promising sources of leucocratic granites. One of the sections of this place “Vostochny”, which contains a significant amount of reserves of these minerals, is of interest for further exploitation for profit. Despite this, the heterogeneity of the composition of the mined raw materials pushes engineers to develop productive enrichment methods to improve their physical and chemical characteristics.

Muhammad Nabhan Mohamed Nadzri, Azizan Ramli, Juwari Juwari

Start-up operations in small chemical plants represent a critical yet underexplored phase for human error analysis. This study presents the first systematic application of the Cognitive Reliability and Error Analysis Method (CREAM) to assess human reliability during start-up operations of three utility systems steam boilers, water-cooling pumps, and air compressors in a small Malaysian chemical plant. Unlike existing studies that focus on routine operations or large-scale facilities, this research addresses the unique challenges of manual start-up procedures in resource-constrained environments. Both basic and extended CREAM versions were applied using Hierarchical Task Analysis (HTA) validated by seven experts with more than 10 years of experience. The analysis revealed that all systems predominantly operated under tactical control mode, with human error probabilities ranging from 0.073 to 0.121. Water-cooling pump operations showed the highest risk (0.320) due to time constraints and collaboration quality issues, while boiler operations demonstrated the lowest risk (0.014) through structured procedures. Critical failure modes were identified in observation and timing-related tasks, particularly in speed verification and parameter adjustment subtasks. This study demonstrates CREAM's applicability to small-scale chemical plant start-ups and provides quantitative reference values for integrating human reliability assessment into Process Safety Management (PSM) systems. The findings support targeted interventions including procedural standardization, enhanced training for high-risk subtasks, and improved shift handover protocols to reduce human error in early-phase operations.

Manuel Palma Banos, Joel D. Kress, Rigoberto Hernandez et al.

A data-driven computational method is introduced to extract chemical reaction mechanisms from time series chemical concentration data. It is realized through the use of dynamic symbolic regression in which a sparse analytical form for a dynamical system is discoverable from the underlying data. We specifically develop the stoichiometrically-informed symbolic regression (SISR) method to address a standing challenge in complex chemical reaction networks: Given a time-series dataset of concentrations of several components, what is the mechanism and the associated rate constants? SISR finds the optimal mechanism, kinetic equations and rate constants by combining differential optimization with a genetic optimization approach that searches a symbolic space of possible reaction mechanisms. Use of SISR in several paradigmatic examples spanning linear and nonlinear reaction schemes results in excellent agreement between true and predicted mechanisms, including when the method is applied to noisy data. The advantages of a stoichiometrically-informed approach such as SISR to address reaction discovery is illustrated through comparison with the use of generic state-of-the-art data-driven approaches.

Alexander Otto, T. Grube, S. Schiebahn et al.

The utilization of ‘captured’ CO2 as a feedstock in the chemical industry for the synthesis of certain chemical products offers an option for preventing several million tons of CO2 emissions each year while increasing independence from fossil fuels. For this reason, interest is increasing in the feasibility of deploying captured CO2 in this manner. Numerous scientific publications describe laboratory experiments in which CO2 has been successfully used as a feedstock for the synthesis of various chemical products. However, many of these publications have focused on the feasibility of syntheses without considering the ancillary benefits of CO2 emissions reduction if the CO2 is sourced from effluent or the potential profitability of this process. Evaluating these environmental and economic benefits is important for promoting the further development of benign CO2 applications. Given the multitude of CO2 utilization reactions in the laboratory context, an initial assessment must be undertaken to identify those which have the most potential for future technical exploration and development. To achieve this, 123 reactions from the literature were identified and evaluated with the help of selection criteria specifically developed for this project. These criteria incorporate both the quantitative potential of reducing CO2 and possible economic benefits of these syntheses. The selected reactions are divided into bulk and fine chemicals. Of the bulk chemicals, formic acid, oxalic acid, formaldehyde, methanol, urea and dimethyl ether, and of the fine chemicals, methylurethane, 3-oxo-pentanedioic acid, 2-imidazolidinone, ethylurethane, 2-oxazolidone and isopropyl isocyanate, mostly fulfil the selection criteria in each category.

Afsah Mumtaz, Shakil Ahmed

The biosynthesis of silver nanoparticles is an emerging field in nanotechnology. There are several different methods to prepare silver nanoparticles depending upon their uses such as in the pharmaceutical and textile industries, and the field of medicine. One of the most important applications of silver nanoparticles is their antifungal activity against different plant pathogenic fungi. In this study, a cost-effective and environment-friendly method was used to synthesize silver nanoparticles using leaf extract of different varieties of Mangifera indica L. The varieties used in this study were Fajri, Malta, Sinduri, Sufaid Chaunsa, and Langra. The aqueous extract of the leaves of mango acted as reducing and stabilizing agents for the silver nanoparticles. The formation of silver nanoparticles was confirmed by the UV-Vis spectroscopy in which a surface plasmon resonance peak within the range of 448-454 nm was observed. FTIR analysis was also performed which showed the bands between 3738 cm-1 to 432 cm-1 which confirmed the presence of different chemical groups. Silver nanoparticles were further characterized by the scanning electron microscopy which revealed the sizes of the nanoparticles within the range of 12-235 nm. After characterization, the antifungal activity of biosynthesized silver nanoparticles was evaluated. From the results, it was concluded that all the varieties showed a greater inhibitory effect at the concentration of 100 mg/L, but it was observed that silver nanoparticles prepared by the leaf extract of cv. Fajri exhibited a greater inhibitory effect against Aspergillus niger having a percent inhibition of 79.8%.

Maria P. Spínola, Ana R. Mendes, José A. M. Prates

The cyanobacterium <i>Limnospira platensis</i>, vulgarly Spirulina, has gained significant attention due to its high protein content, rich bioactive compounds, and health benefits, making it a valuable resource in biotechnology, nutraceuticals, food supplements, biopharmaceuticals, and cosmetics. Recent advancements in fermentation technology have considerably improved the efficiency, scalability, and cost-effectiveness of <i>L. platensis</i> production while addressing environmental sustainability and enhancing product quality. Based on well-recognized databases (Google Scholar, PubMed, Scopus, Web of Science), this review explores the latest developments in <i>L. platensis</i> fermentation, emphasizing strain improvement, bioprocess engineering, and optimization of fermentation parameters. It also examines key factors such as bioreactor design, downstream processing, and innovative monitoring technologies aimed at maximizing biomass yield and bioactive compound production. Additionally, emerging applications of fermented <i>L. platensis</i> in various industries and future perspectives, including large-scale production, regulatory barriers, and biosafety considerations, are discussed. These insights provide a comprehensive outlook on the future of <i>L. platensis</i> fermentation in biotechnological applications.

Uri Zamir, Joshua H. Baraban, Peter Fjodorow et al.

Meeting the demands of sustainable energy economy requires diagnostics of the chemical processes surrounding future fuels and contemporary combustion applications. Pioneered in 1970, Intracavity Laser Absorption Spectroscopy (ICAS) has evolved to be a powerful instrument in the toolbox of combustion diagnostics. It owes its ultra-high sensitivity to the enhancement of the effective absorption pathlength by placing the absorber inside the cavity of a broadband laser. In this review we introduce the complementary strengths of ICAS to other methods: ultra-high sensitivity to narrowband absorption alongside the immunity to broadband losses, multiplexed detection and (µs-scale)-temporal resolution. We outline the basic concepts and features of ICAS, focusing on the laser dynamics regime where an absorbing sample in the laser resonator yields the well-known Lambert-Beer law. We chart the progress made over the years in visible (dye-jet laser) and near infrared (fiber laser) ICAS speciation in flames, by highlighting case studies where species like long considered ''hard-to detect'' 1CH2 and HCO radicals, along with O-atoms, C2, NH2, HNO, CN, and HCN were measured, as well as thermometry and speciation applications demonstrated in shock tubes, flow-cells and flames based on (stationary or time-resolved) measurements of multicomponent spectral matrices containing lines of CH4, C2H2, CO2, CO, OH and H2O. We highlight the contributions of ICAS in gas-phase nanomaterial synthesis, exemplified in prototypical iron-doped flames and discuss prospective applications in spray-flame pyrolysis and metal-powder combustion. Finally, we present advances in the development of lasing media based on Cr2+ and Fe2+-doped chalcogenide crystals and fluoride crystals doped with trivalent lanthanides, that meet the (ICAS-specific) requirement associated with the necessity to have a gain media lasing directly in the desired wavelength range, and therefore to expand this technique into the important mid-infrared and ultraviolet spectral ranges.

Wenhao Gao, Shitong Luo, Connor W. Coley

We introduce SynFormer, a generative modeling framework designed to efficiently explore and navigate synthesizable chemical space. Unlike traditional molecular generation approaches, we generate synthetic pathways for molecules to ensure that designs are synthetically tractable. By incorporating a scalable transformer architecture and a diffusion module for building block selection, SynFormer surpasses existing models in synthesizable molecular design. We demonstrate SynFormer's effectiveness in two key applications: (1) local chemical space exploration, where the model generates synthesizable analogs of a reference molecule, and (2) global chemical space exploration, where the model aims to identify optimal molecules according to a black-box property prediction oracle. Additionally, we demonstrate the scalability of our approach via the improvement in performance as more computational resources become available. With our code and trained models openly available, we hope that SynFormer will find use across applications in drug discovery and materials science.