Kuwait Journal of Science最新文献

Seagrasses are in danger due to anthropogenic activities causing a reduction in seagrass area and global damage. It is crucial to map seagrass distribution, as there is limited information on its existence. Sentinel-2A satellite provides high-resolution multispectral data with a 10-m resolution. The study aimed to evaluate the ability of Sentinel-2A imagery from the Google Earth Engine (GEE) platform to classify with the random forest (RF) algorithm in mapping seagrass in shallow water and various other objects in the study area. The results showed the area's presence of seagrass, coral, sand, sand seagrass, and rubble. Also, the photo transect method was used for collecting field data. The random forest algorithm had an accuracy of 76% in classifying each of the five classes. The combination of Sentinel-2A imagery and random forest algorithms can provide insight into the status and distribution of seagrass.

In this work, the stems, leaves, and flowers of Ruta chalepensis L., R. graveolens L., and R. montana L. harvested in Morocco were subject to a comparative study to determine the phytochemical composition, antioxidant capacities, and the content of total phenols and flavonoids. For this purpose, 45 crude extracts (CEs) were prepared using different solvents, including water, ethyl acetate, methanol, ethanol, and hexane. Upon undergoing secondary metabolites screening, it was discovered that the different parts of three Ruta species contain a high level of secondary metabolites such as alkaloids, catechic tannins, flavonoids, coumarins, sterols, and triterpenes. This was confirmed by the results of the quantitative analysis, which proved that the three Ruta species contain a significant amount of total phenolic compounds, ranging from 27.05 to 213.42 mg GAE/g CE. With regard to antioxidant capacities, antiradical power (ARP) results prove that the majority of CEs have great ARP (were within the range of 0.42–1.99) compared to the BHT (butylated hydroxytoluene) standard (0.33 APR). In addition, the results of total antioxidant capacity (TAC) analysis of Ruta CEs showed good TAC (varies between 37.67 and 396.80 mg AAE/g CE).

Fusarium oxysporum f.sp. cubense (Foc) is a fungus that not only causes disease while bananas are being grown, but it also causes begetting after bananas are harvested, which limits the production of bananas. Zingiberaceae plants contain a high number of extractable secondary metabolites that are regarded to have effective antifungal activities. However, in order for the compounds to be suitable for use, they must be tested by modifying the polarity in the extracting solvent. In this study, four Zingiberaceae species were examined, namely Zingiber officinale, Curcuma longa, C. zanthorrhiza, and Alpinia galanga. The extraction of rhizomes of each plant was accomplished by using solvents with distinct polarity index (PI) viz. water (PI 9.0); a mixture of 50% water and 50% ethanol (PI 7.1); ethanol (PI 5.2); and n-hexane (PI 0.0). The anti-Fusarium evaluation of these 16 extracts was carried out in vitro by implementing the pour plate method in potato dextrose agar (PDA). Our results showed that the C. zanthorrhiza n-hexane extract possessed the greatest antifungal activity among other extracts. The fungal inhibition ability of the extracts was negatively correlated with the increase in solvent polarity index. In order to comprehend our understanding of the antifungal activity, the chemical compositions of each extract were identified through non-targeted Gas Chromatography–Mass Spectrometry (GC-MS), showing the main components of the n-hexane extracts were terpenes and terpenoids. Particularly, C. zanthorrhiza n-hexane extract contained, with the percentage of abundance in parentheses, germacrene B (22.99%), β-farnesene (14.72%), curzerene (10.87%), 2-bornanone (9.60%), α-curcumene (9.32%), zingiberene (8.30%), β-curcumene (6.36%), β-elemene (5.31%), caryophyllene (3.36%), cedrene (2.73%), α-bergamotene (1.36%), and humulene (0.20%). As conclusion, this crude extract or its pure chemical constituents have potential application as biofumigant to control Foc in postharvest banana.

This study focuses on identifying the degree of shoreline changes on the north coast of Java Island (Indonesia), particularly the Batang Regency segment, using multiple data sources: Landsat 9 and 8, Landsat 5 TM, and PlanetScope spanning from 2000 to 2023. The degree of change was obtained by statistically calculating net shoreline movement (NSM), linear regression rate (LRR), and end-point rate (EPR) using the digital shoreline analysis system (DSAS) software. The three rate-of-change statistics were used to calculate the multidecadal shoreline change prediction or projection for the next 10 and 20 years using a Kalman filter-based model with a simple data assimilation technique. Based on these results, NSM indicated that the shoreline experienced a total accretion and erosion of 361.04 and 111.58 m, respectively, from 2000 to 2023. Over these years, the highest accretion rate reached 16.44 m/year (according to LRR) or 15.83 m/year (EPR), while the maximum erosion rate was up to 11.34 m/year (LRR) or 9.43 m/year (EPR). The use of two data sources with different spatial resolutions produces varying statistical values, which depend on the degree of detail and complexity of the data derived from the source imagery. The coastline prognosis model produced with the Kalman filter shows that the entire coastline in Batang Regency will most likely experience an average accretion and erosion of 18.03 and 21.42 m, respectively, in 10 years, while that in the next 20 years will be 26.38 and 33.3 m, respectively.

The current study investigates the effect of adding a low-cost biomaterial (sawdust biomass) to kaolinite clay on the properties of insulating refractory materials. Natural kaolinite clay from NW Tunisia has been selected for porous ceramic preparation due to its high alumina content (23.64%) with low impurities, especially iron and alkaline oxides. For this study, a set of cylindrical samples were prepared from mixtures of Tabarka clay with different proportions of sawdust (10, 15 and 20%). Those green specimens were pressed and sintered to 1350 °C for 2 h. Experimental data showed that the increase in sawdust proportion increased the open porosity from 24 to 35%. SEM images showed higher important porosity with higher biomass addition. Similarly, bulk density and compressive strength decreased to 1.65 g/cm³ and 17 MPa, respectively. Mullite phase was also generated by the abundant alumina and silica in the raw feed. Several ceramic specimens were also manufactured under optimal conditions: sawdust (20%), pressure (10 kN), and sintering at 1200, 1250 and 1300 °C. The obtained ceramics showed higher porosity (57%), but lower bulk density (1.13 g/cm³). These are the required standards for silica-alumina insulating materials, confirming the possible valorization of kaolinite clay from Tunisia for refractory insulating ceramic.

Microbes are prevalent in wastewater, degrading organic matter that impact the environment. In recent years, wastewater treatment plants have been used to process treated water for domestic purposes, sustaining groundwater resources for the future. The current study assessed the present microbial species in the aeration tanks for the secondary wastewater treatment stage in the Sulaibiya Wastewater Treatment and Reclamation Plant, Kuwait. Biweekly wastewater samples were collected for a period of three months from October 2022 to December 2022 from the aeration tanks. The collected wastewater samples were analyzed for microbiological parameters including total coliform, fecal coliform, Salmonella, and E. coli. Further, the microbial species were identified using the Biolog Omnilog Instrument. The results indicated that a total of 45 bacterial species isolates were identified with the most dominant genus being Bacillus with twenty-one isolates. Though Bacillus is common in aeration tanks, the presence of Bacillus thuringiens/cereus is rare and their existence could be due to the change in climatic conditions such as rainfall, dust and wind. Therefore, the study recommends that all microbial groups should be identified at all treatment stages including, primary, secondary, tertiary, and advanced treatment stages to ensure the complete removal of microbes.

The daily air quality indices (AQIs) for pollutants, including particulate matter (PM₁₀ and PM_2.5), carbon monoxide (CO), nitrogen oxides (NO₂), ozone (O₃), and sulfur dioxide (SO₂), were evaluated for the period of 2019–2022 in Al-Jahra City, Kuwait. This study is designed to (1) evaluate overall and seasonal changes in pollutants, (2) investigate the correlation for PM₁₀ and PM_2.5 and other pollutants during each season, and (3) examine the best model for prediction of air pollutant concentration of PM₁₀ and PM_2.5. An assessment of air quality indices was carried out by using different algorithms models, including random forest (RF), an artificial neural network (ANN), and extreme gradient boosting (XGBoost). The overall level of PM₁₀, PM_2.5, and SO₂ pollutants shows an increasing trend from 2019 to 2022, reaching their highest in 2022 with a significant decrease in 2020 during COVID-19 lockdown restrictions. The pollutants CO and O₃ reached their peak in 2021.The obtained results showed that the PM₁₀ and O₃ levels are higher in the summer, whereas PM_2.5, NO₂, and CO were recorded at the highest levels during spring, autumn, and winter respectively due to a variation in the meteorologic condition. Furthermore, during the winter season, the PM₁₀ is positively correlated with CO (r_p = 0.401), NO₂ (r_p = 0.121), and SO₂ (r_p = 0.119) AQIs while PM_2.5 is significantly positively correlated with the CO (r_p = 0.198), O₃ (r_p = 0.310), and SO₂ (r_p = 0.129) AQIs. In contrast, the performance of XGBoost is a more reliable predictor for PM₁₀ and PM_2.5 levels.

Hydroponics is a viable alternative for urban contexts with limited resources and space since it offers efficient and low-maintenance planting methods. This study specifically examines the development of synthetic soil by utilizing hydrochar obtained from wild weeds (Amaranthus sp.). X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and field-emission scanning electron microscopy (FE-SEM) were used to study the hydrochar after it was made using the hydrothermal carbonization method. The analysis showed that the hydrochar had an undefined crystal structure and an uneven, varied porosity. The expansion capacity test clearly showed a significant growth potential of 32%. Nevertheless, the water retention tests revealed a progressive decline in the capacity to retain water as time passed. The kinetics model was used to simulate the release of NPK from the counterfeit soil. The P and K components adhered to a first-order model, but the N elements adhered to the Kosmeyer-Peppas model. The use of artificial soil as a substrate for kale plants had excellent outcomes, with the highest growth rate of 0.75 cm reported on day 7. Subsequently, the growth stabilized and gradually decreased to 0.3 cm by day 21. Hydrochar generated from wild weeds (Amaranthus sp.) is a practical choice for hydroponic farming systems, as it provides fertilizer storage and slow-release advantages.

With its unique corrosion resistance, light weight, mechanical strength, and biocompatibility, TNZ is a versatile metal alloy that is used in the aerospace and medical industries. The current study aims to investigate the effect of milling time (2, 12, 24, and 36 h) on the nanostructured ternary alloy Ti-25Nb-25Zr (TNZ) prepared by high energy ball milling, a process involving the use of a high-energy ball mill to mix and grind the alloy powders, on its structural, physical, and photocatalytic characterizations. The alloys' characteristics, such as morphology, structural properties, relative density/porosity, surface roughness, hardness, and Young's modulus, were evaluated using SEM, XRD, surface profilometer, and microdurometer, respectively. The photocatalytic characterization was conducted by measuring their absorbance as a function of time using a spectrophotometer of visible and ultraviolet light in the wavelength range of 250–650 nm. Results showed that the crystallite and mean pore size reduced with increasing milling time, with the smallest values of 25 nm and 34 μm, respectively, after 36 h. This indicates that longer milling times result in a more compact and uniform structure, which could enhance the mechanical properties of the alloy. Structural characterization shows that the amount of the β-Ti phase increased with increasing milling time, resulting in the spherical morphology and texturing of the synthesized alloys. The milled alloys' structural evolution and morphological changes were sensitive to their milling times. Also, the relative density, Young's modulus, and hardness increased, reaching values of 89 %, 105 GPa, and 352 HV, respectively, due to grain size decreasing with increasing milling time. This suggests that longer milling times lead to a denser and harder alloy, which could be beneficial for its use in total hip prostheses. The photocatalytical characterization demonstrated that the degradation of orange II (OII) increased with increasing milling time. The Ti-25Nb-25Zr catalyst gave the best degree of degradation, which meant that the decolorization process could be operated rapidly and at a relatively low cost without UV irradiation.

This study utilized data from the NASA Gravity Recovery and Climate Experiment (GRACE) to examine the variability of the terrestrial water storage anomaly (TWSA) in Iraq between 2002 and 2019. The analysis focused on six grid cells representing the Iraqi territory. The season trend decomposition (SLT) method was used to decompose the signal time series of TWSA to reveal the seasonality, trend, and random noise for the six GRACE blocks. Results proved that Block01 in northwestern side of Iraq, experienced a significant reduction in TWS between 2002 and 2009, followed by a negative linear trend until 2015, and then a positive trend. Block02 which is located in the northeastern part of Iraq showed a decreasing trend in TWS until 2008, after which it had a positive trend. Block03 in the western central side of Iraq reveals a decrease in TWS from 2002 to 2008, followed by a negative linear trend until 2016, and then a positive trend. Block04 in the eastern Mesopotamian plain had a minor increase in TWS until 2006, followed by a substantial decrease until 2016, before stabilizing and showing a positive trend. Block05 in the southwestern side of Iraq demonstrated a continuous decline in TWSA. In contrast, TWS increased in block6 on the southeastern side from 2002 to 2007, then decreased from 2007 to 2009. TWSA levels remained stable from 2009 to 2016, then increased from 2016 to the end of 2019. The seasonal fluctuations in TWS varied across the blocks, but generally, surpluses were observed in winter and spring, while deficits were observed in summer and autumn. The shortage in TWS is attributed to drought and excessive use of groundwater for irrigation. The recent positive trends in TWS in some blocks suggest that the drought may be coming to an end, but further analysis is necessary to reach a definitive conclusion.