Predominant Shapes Research Articles

OS FULGURITOS DE ARACATI, NO ESTADO DO CEARÁ

This work describes the first known occurrence of fulgurites in Ceará coastline found in the Aracati county. Fulgurites are the result of the natural process of the incidence of electrical discharges of lightning on sand, soil and rocks. The product of this process in sand and soil is a new rock with unique recrystallization characteristics of the material exposed to the discharge. In some occurrences around the world, there is a record of vitrification observed with the naked eye, which was not possible in Aracati. Here, the samples collected are representative of two predominant shapes: oblong and cylindrical. The first form presents cohesion of sand grains in the central part of the sample and friability on the crests, without presenting the cavities characteristic of the cylindrical shape. This, in turn, presents differences in density, fragility and color in relation to the oblong shape. These characteristics are very similar to those of the petrified roots described in the municipality of Itarema as rhizoconcretions, however, Prof. Dr. Marcondes Lima da Costa in Aracati, in March 2024, made it possible to investigate the material with a focus on fulgurites.

Spatial and seasonal variations of atmospheric microplastics in high and low population density areas at the intersection of tropical and subtropical regions

There is limited information regarding spatial and seasonal variations of atmospheric microplastics (MPs) and factors influencing MPs at the intersection of tropical and subtropical regions. A one-year study was conducted at sites in a high-population-density village (HPDV) and a low-population-density village (LPDV) in Taiwan to investigate the characteristics and influencing factors of airborne MPs. The predominant shapes, sizes, and polymer compositions of MPs were fragments, 3 to 25 and 26–50 μm, and polyamide at both sites. Seasonal variation in MP morphologies was not significant. Average MP concentrations were 2.20 ± 2.97 particles/m3 and 1.92 ± 2.35 particles/m3 at the HPDV and LPDV sites, respectively, and did not differ significantly. Higher concentrations and smaller sizes of MPs were found during the summer at both sites, while the predominant wind direction was southerly or southwesterly. In samples with temperatures exceeding 25 °C, the temperature was positively associated with MP concentrations at both the HPDV and LPDV sites. These results reflect that temperature influences the variations in the concentrations and sizes of MPs at our study site. Future research should consider the adverse risks of MP inhalation during the hot season. Moreover, when sites with different population densities and levels of human activity are closed, MP concentrations will not differ significantly between these areas since airflow can transport these particles from high-population-density areas into low-population-density areas in a short time.

First Evidence of Microplastic Ingestion by Riverine Fish From the Freshwater of Northwest Peninsular Malaysia.

In a baseline study, we investigated microplastic contamination in fish from the Pinang and Kerian Rivers in Northwest Peninsular Malaysia. In recognition of the growing concern over microplastic pollution in aquatic environments, we aimed to assess the abundance and characteristics of microplastics ingested by various fish species. Fish samples were collected from local fishermen, followed by a digestion process using 10% potassium hydroxide (KOH). Microplastics were isolated and analyzed through visual examination and attenuated total reflectance Fourier transform infrared spectroscopy. The results revealed a high prevalence of microplastics, with Johnius borneensis and Oreochromis sp. exhibiting the highest abundance, averaging 48.6 and 42.8 microplastics/g, respectively. The predominant shapes were fibers (55.6%) and fragments (25.9%), with colors primarily transparent (48.19%) and black (30.12%). Our results indicate significant contamination levels in freshwater fish, emphasizing the need for further research and effective mitigation strategies. These findings provide crucial baseline data on microplastics in Malaysian freshwater ecosystems. Environ Toxicol Chem 2024;43:2189-2198. © 2024 SETAC.

Influence of agricultural activity in corn farming on airborne microplastic in surrounding elementary school

Microplastics (MPs) have been widely detected in agricultural soils, and agricultural activities have been identified as an important factor influencing the abundance of MPs in the air. However, no studies have investigated whether agricultural activities are contributors to airborne MPs in buildings near farms. We collected airborne MP samples using an active sampling method from an elementary school near corn farms during different cultivation stages to assess the impact of agricultural activities on MPs in the study school near farms. Our data showed that the predominant shapes, sizes, colors, and polymer compositions were fragments, 2–50 μm, black or grey, and polyethylene terephthalate, respectively, during all cultivation stages. The highest and lowest MP concentrations were recorded during the land preparation (56.8 ± 7.4 particles/m3, August 2022) and growth (2.5 ± 1.8 particles/m3, February 2022) stages, respectively. A multiple-path particle dosimetry model revealed that the deposition fractions of MPs in humans were highest in the head; the highest and lowest deposition rates and fluxes of MPs in the airway were found during the land preparation and growth stages, respectively. The concentration of MPs did not present a positive correlation with potassium or crustal elemental concentration; however, it did show a positive association with temperature value. Therefore, our data did not show that corn cultivation influences MP concentrations in the study school near corn farms; instead, temperature was an important influencing factor.

Microplastic pollution in beach sediments in the Dapoli coast, Maharashtra, the western peninsular region of India

In coastal ecosystems, microplastics (<5 mm plastic particles) are a common occurrence, presenting a pressing global concern, especially on beaches where increased human activity and inadequate waste management exacerbate the issue of plastic pollution. This research investigates the abundance and characteristics of microplastics at six tourist beaches along the western coast of Dapoli, Maharashtra. The sediment samples were collected and subjected to density separation, followed by microscopic observation and shape, size, color, and polymer characterization. The results revealed that microplastic particles ranged in size from 200 to 3000 µm (n=200 particles). The abundance was observed highest in Murud beach with 153 ± 26.8 items kg−1 dw, possibly attributed to increased tourist activity, whereas the lowest abundance of 91.1 ± 16.8 items kg−1 dw was observed in Kelshi beach, likely due to its lower visitor traffic and population density. The predominant shapes observed were fragments and transparent, black, and blue as the dominant colors. Additionally, most samples exhibited spectra resembling High-Density Polyethylene (HDPE), Polypropylene (PP), Polystyrene, and Polyvinyl Chloride (PVC). This baseline study urges awareness for reducing plastic waste and protecting coastal environments from microplastic pollution. Further research is needed to identify specific sources and understand the toxic effects on marine life, contributing to our knowledge of environmental threats posed by microplastics.

Human activities altered the enrichment patterns of microplastics in mangrove blue carbon ecosystem in the semi-enclosed Zhanjiang Bay, China

Mangroves, as the key blue carbon ecosystem, are considered ‘potential sinks’ for microplastics (MPs) in the land-ocean interface zones. However, there is limited understanding of enrichment patterns of MPs in mangrove blue carbon ecosystem, particularly in relation to human activities. This study explored the abundance, composition, and diversity of MPs in mangrove and non-mangrove sediments in Zhanjiang Bay (ZJB) to investigate the effects of human activities on MPs enrichment patterns in the blue carbon system. The results showed that MPs were widely prevalent in all sediment samples, and the abundance of MPs was significantly higher in all mangrove sediments than in non-mangrove sediments (P &amp;lt; 0.05). Furthermore, the average abundance of MPs was found to be 263.67 ± 85.25 items/kg in non-mangrove sediment samples, whereas in mangrove sediment samples, it was 618.17 ± 71.75 items/kg. The average abundance of MPs in mangroves was about 1.6 times higher than that in non-mangroves, indicating that mangroves have an interception effect on MPs, and human activities are the key factor leading to the difference in MPs enrichment patterns between mangroves and non-mangroves. Furthermore, the predominant MPs shapes in both mangroves and non-mangroves are fragments, with multicolor and green being the most common colors and most MPs sizes ranging between 100 and 330 µm. Besides, there was no significant relationship found between MPs abundance and particulate organic carbon (P &amp;gt; 0.05), indicating that MPs pollution didn’t significantly alter the natural POC pool in ZJB. Overall, this study provided important baseline information on MPs pollution in the mangrove blue carbon ecosystems in ZJB, which was implications for future mitigation of MPs pollution and the management of mangrove ecosystem.

Food grain quality: Analysis of physical, biometric, and colorimetric properties to promote consumption

This research focused on analyzing the biometric, colorimetric and morphological characteristics of thirty seeds, covering legumes, cereals and oilseeds. Thirteen legumes, fourteen cereals and three oilseeds were collected from three different locations. The methodology used was descriptive, applying multivariate multiple factorial and cluster analysis. The results showed variability between biometric, chromatic and morphological characteristics among the seeds. Predominant shapes include circular, oval, oblong, less frequently kidney and lanceolate. Significant differences in biometric parameters stand out, evidencing similarities in colorimetric parameters. Specifically, Pallar and Bean exhibited greater equatorial dimensions, length, weight, 100 g weight, area and perimeter, While peanut and Chickpea presented greater thickness. In terms of colorimetry - luminosity, Pallar, Yellow corn and Tarwi presented higher values unlike Black lentils, Purple corn and Black beans, being less luminous. Multivariate tests revealed the formation of four groups based on the parameters studied. This study provides valuable information about the different seeds, establishing a basis for their propagation and improvement in the Peruvian context.

A computed tomography-based retrospective study on the foramen ovale and foramen spinosum in a Nigerian population

Abstract Background: This study investigated the shapes and dimensions of the foramen ovale (FO) and foramen spinosum (FS) in a specific population sample from Delta State, Nigeria, emphasizing their significance in various neurosurgical procedures. Materials and Methods: Following ethical clearance, this retrospective study analyzed 250 brain computed tomography (CT) images from the Radiology Department of a teaching hospital in Delta State, Nigeria. The sample included images from 100 females and 150 males, all aged 18 years or older. The dimensions of the FO and FS were measured on axial sections using a standardized protocol. Statistical analyses were conducted with Statistical Package for Social Sciences (IBM, Chicago, Illinois, United States) software, categorizing data by gender and age groups. Inferential statistics, including Student t test, analysis of variance, and Pearson’s correlation, were performed, with findings considered significant at P &lt; 0.05. Results: The predominant shapes of the FO and FS were oval and round, respectively. Significant side differences were observed in the length of the right FS (P = 0.040). Gender differences were noted in the length of the bilateral FO (P = 0.010) and the width of the left FO (P = 0.001). A significant correlation with age was found for the width of the left FO (P = 0.006) and the distance from the right FO to FS (P = 0.037). The FS was absent in 24 cases (9.6%). Conclusion: This study highlights age-, side-, and gender-related differences in the shapes and dimensions of the FO and FS. It emphasizes the importance of precise preoperative radiological assessments to ensure optimal outcomes for neurosurgical planning.

Occurrence of microplastics in edible tissues of livestock (cow and sheep).

Plastic contamination is widely recognized as a major environmental concern due to the entry of small plastic particles into the food chain, thereby posing potential hazards to human health. However, the current understanding of microplastic (MP; < 5 mm) particles in livestock, which serve as an important food source, is limited. This study aims to investigate the concentration and characteristics of MPs in edible tissues of cow and sheep, namely liver, meat, and tripe, obtained from butcher shops in five areas of Bushehr port, Iran. The mean concentration of MPs in different tissues of cow and sheep were 0.14 and 0.13 items/g, respectively. Among the examined tissues, cow meat exhibited the highest concentration of MPs, with a concentration of 0.19 items/g. Nylon and fiber were identified as the predominant polymer types and shapes of MPs found in cow and sheep tissues, respectively. Furthermore, no statistically significant difference was observed in MP concentration across different tissues of cow and sheep. Significantly, this study highlights the elevated hazards associated with exposure to MPs through the consumption of edible cow and sheep tissues, particularly for children who consume meat. The results underscore the potential transfer of MPs from the environment to livestock bodies through their food, contamination during meat processing, and subsequent health hazards for consumers.

Characterization of arrowroot (Maranta arundinacea) starch as a potential starch source for the food industry

Arrowroot is an underutilized tuber crop in Sri Lanka and the characterization of starch was done to identify its nutritional, physicochemical, and functional properties to evaluate its potential for use in the food industry. This study distinctly advances the field of arrowroot starch characterization by providing more characterization techniques for starch samples from Sri Lanka. Arrowroot starch colour was closely similar to colour of wheat flour indicating that the effect of colour is minimum when replacing wheat flour. Oval, spherical, and irregular globular shapes were the predominant starch granule shapes for arrowroot. The average length of starch granules was 44.99 ± 1.27 μm while the width of granules was 31.44 ± 0.58 μm. The least gelation concentration was 8.0% indicating its better gel-forming ability. The nutritional composition of arrowroot starch consisted of low crude protein (0.72 ± 0.02%), crude fat (0.26 ± 0.19%), and crude fiber (1.00 ± 0.09%) contents indicating the purity of starch. Sodium, Potassium, Calcium, Iron, and Zinc contents were 52.6 mg/kg, 4312.95 mg/kg, 382.67 mg/kg, 9.07 mg/kg, and 2.59 mg/kg, respectively. Results of flour densities demonstrated the potential of arrowroot starch to be used in the pharmaceutical industry. Arrowroot starch had high viscosity defining its potential as a thickener. The starch also had high swelling power and solubility indices while solubility was positively correlated with viscosity (0.679; P > 0.05). The low moisture absorbance indicates a longer shelf life of stored arrowroot starch. Onset temperature (To) of 75.02 °C, peak temperature (Tp) of 77.95 °C, and conclusion temperature (Tc) of 82.43 °C were resulted from DSC thermogram. Arrowroot was identified as an A-type starch from x-ray diffractometry and the FT-IR spectrum of arrowroot was identical to starch and presented the carbohydrate nature of starch. Thus, arrowroot starch has a high potential to be used in the food industry based on its functional properties.

Removal efficiencies of microplastics of the three largest drinking water treatment plants in Bangladesh

Drinking water treatment plants (DWTPs) are intended to provide safe water to the municipality, typically by treating surface waters from rivers, lakes, and streams. Regrettably, all of these water sources for DWTPs have been reported to be contaminated by microplastics (MPs). Hence, there is an urgent need to investigate the removal efficiencies of MPs from raw waters in the conventional DWTPs anticipating public health concerns. In this experiment, MPs in the raw and treated waters of the three major DWTPs of Bangladesh, having different water treatment processes, were evaluated. The concentrations of MPs in the inlet points of Saidabad Water Treatment Plant phase-1 and 2 (SWTP-1 and SWTP-2), which share a similar water source of the Shitalakshya River, were 25.7 ± 9.8 and 26.01 ± 9.8 items L−1. The third plant, Padma Water Treatment Plant (PWTP) utilizes water from the Padma River and had an initial MP concentration of 6.2 ± 1.6 items L−1. The studied DWTPs, with their existing treatment processes, were found to reduce the MP loads substantially. The final MP concentrations in treated waters of SWTP-1, SWTP-2, and PWTP were 0.3 ± 0.03, 0.4 ± 0.01, and 0.05 ± 0.02 items L−1 with the removal efficiencies of 98.8, 98.5, and 99.2 %, respectively. The considered size range of MP was 20 μm to <5000. Fragments and fibers were the two predominant MP shapes. In terms of polymer, the MPs were polypropylene (PP, 48 %), polyethylene (PE, 35 %), polyethylene terephthalate (PET, 11 %), and polystyrene (PS, 6 %). The field emission scanning electron microscopy-energy dispersive X-ray spectroscopy (FESEM-EDX) revealed the fractured and rough surfaces of the remaining MPs, which were also found to be contaminated with heavy metals, like lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As), copper (Cu), and zinc (Zn). Hence, additional initiatives are required to remove the residual MPs from the treated waters to safeguard the city dwellers from potential hazards.

Particle shapes and infrared extinction spectra of nitric acid dihydrate (NAD) crystals: optical constants of the β-NAD modification

Abstract. Satellite- and aircraft-based mid-infrared measurements of polar stratospheric clouds (PSCs) have provided spectroscopic evidence for the presence of β-NAT (nitric acid trihydrate) particles. Metastable nitric acid hydrate phases such as α-NAT and α-NAD (nitric acid dihydrate) have been frequently observed in laboratory experiments but not yet detected as a constituent of PSCs in atmospheric measurements. As for the β-NAD modification, its formation was first observed in X-ray diffraction measurements when the low-temperature α-NAD phase was warmed to a temperature above 210 K. Its infrared spectrum has been reported, but so far no optical constants have been derived that could be used as input for infrared retrievals of PSC composition. In this work, we show that β-NAD particles were efficiently formed in isothermal heterogeneous crystallisation experiments at 190 K from supercooled HNO3/H2O solution droplets containing an embedded mineral dust or meteoric smoke particle analogue. An inversion algorithm based on a T-matrix optical model was used to derive for the first time the mid-infrared complex refractive indices of the β-NAD modification from the measured extinction spectrum of the particles. In contrast to the heterogeneous crystallisation experiments, the α-NAD phase was formed when the HNO3/H2O solution droplets did not contain a solid nucleus and crystallised homogeneously. Using a light-scattering detector that recorded two-dimensional scattering patterns of the crystallised NAD particles, we were able to determine predominant shapes of the α- and β-NAD crystals. We found that α-NAD grew into elongated, needle-shaped crystals, while β-NAD particles were compact in shape. This agrees with previously reported images of α- and β-NAD particles grown on the cryo-stage of an environmental scanning electron microscope. While direct evidence for the existence of metastable NAD in the polar stratosphere is still lacking, our experiments add to the wealth of previous laboratory studies that have identified various conditions for the rapid growth of metastable compositions. In the atmosphere, these could be intermediate states that transform into thermodynamically stable NAT on longer timescales in aged PSCs.

Dynamic Behavior of Connected Structures

The effect of connected structureonSMK Bukit Tinggibuildingwas investigatedbased ontheirdynamic behaviour. The structure was constructed with four main buildings are interconnected. Ambient vibration testing (AVT) was used to predict the dynamic response and characteristics by using triaxial 1Hz seismometer and CityShark data logger. The AVT signals were analysed using GEOPSY software for Fourier Amplitude Spectral(FAS). All predominant frequencies (fo) and mode shapes were identified and verified with previous research finding using similar testing approach on the same building, but with different instrument of accelerometer sensorand ARTeMIS software processing tool. Five modes of fo were found from the FAS curves from this research, but only four fo were obtained from ARTeMIS analysis. The highest deviation percentage was indicated at the 5thmode of building frequency at 9.5 %, but 0 to 2.5% to the rest frequencies mode (1st to 4th frequencies mode). Ununiformed buildings response behaviour was believed to contribute, and initiate active progressive shear cracking on the slab panels, columns, beam and at the reentrant corners between laboratory and academic buildingsof Building C. It worst when the buildings were struck by several earthquakes’ series. The unsynchronised oscillation between adjacent buildings to Building C had induced couple lateral and torsional deformations. Thestructural and non-structural damages mostly concentrated at the reentrant corners and mid-span of the building, which identical to the location of maximum deflection amplitudes. In conclusion, strict attention must be emphasized on the fo and mode shapes based on their dynamic response and characteristics analyses, which could be altered by the presence of connected structures.

Municipal solid waste sanitary and open landfills: Contrasting sources of microplastics and its fate in their respective treatment systems

Recently, research studies in identifying microplastics (MPs) from various environment has become a notable work, in the view of MPs as emerging pollutants as well as due to many undiscovered high-level impacts to both the environment and living beings. Out of many other sources, municipal solid waste land disposal methods, both controlled landfills and open dumping are observed to be one of the major sources of MPs origination as the predominant quantity of plastic wastes generated is being discarded in those methods. In this study, quantification, and characterization of MPs from the leachate generated from two different solid waste disposal methods and in their respective individual treatment systems were identified. From the studies, 20 different polymer types were spotted with the concentrations in the fresh leachate as 8.80 MPs/L and 9.93 MPs/L in the controlled landfill and open dumping, respectively. The fibers, films, and fragments are found to be the predominant polymer shapes in both the discarding process. Polypropylene and Polyethylene are the main prevailing polymer type in the controlled landfill, whereas polyethylene and polystyrene are in open dumping leachate samples. In addition, the analysis of the treatment system reveals that the ongoing units can remove the MPs from the leachate to some extent. For example, it removed ∼57.1% of MPs from landfill leachate using biological treatment combined with disinfection. Whereas ∼75.2% from the aerated lagoon and membrane treatment for leachate from the open dumping. More fibers with varying polymer types were identified from the effluent of membrane treatment, which is due to the membrane used. Finally, 37 MPs/g from dewatered sludge and ∼500 MPs/L of return sludge indicate the possibility of MPs that can reenter the biological system allowing an increase in the MPs abundance in the biological unit.

Variance of Arrowroot (Maranta arundinacea) Starch Granule Morphology among Five Different Provinces in Sri Lanka

Arrowroot (Maranta arundinacea) is an underutilized tuber crop in Sri Lanka that produces a gluten-free, easily digestible starch. This research aimed to determine the variance of arrowroot starch granular morphology among the plants grown in five different provinces (Western, North-Western, Southern, Sabaragamuwa, Uva). Arrowroot starch granules were observed using the light microscope and scanning electron microscope. Oval, irregular globular and spherical shapes were the predominant granule shapes for arrowroot. The mean percentage of oval shaped granules ranged between 48.46 % - 59.34 %. The length and width of the granules were not significantly different among the five provinces. The length of the starch granules ranged between 42.91 - 45.86 µm while the width ranged between 30.81 – 32.32 µm. Arrowroot flour samples from five different provinces in Sri Lanka were not significantly different with regard to the starch granular morphology and therefore, arrowroot flour can be utilized in the local food industry without concerning their geographical locations.

ANATOMICAL RISK FACTORS FOR THE COMPLICATED POSTOPERATIVE PERIOD IN THE SURGERY OF EXTRACEREBRAL TUMORS OF THE POSTERIOR CRANIAL FOSSA

Tumors of the base of the posterior cranial fossa are among the most difficult for surgical treatment in neurosurgery. Numerous studies are being conducted on the factors that determine clinical manifestations and treatment outcomes. The aim of the study was to study the linear and angular parameters of the posterior cranial fossa in patients with extracerebral neoplasms and to evaluate their effect on the results of surgical treatment. Craniometric study of linear and angular parameters of the posterior cranial fossa was performed in 115 patients with sub-tentorial extracerebral tumors. A computer program was used to determine the longitudinal, transverse and height diameters of the head, the length, width and height of the posterior cranial fossa, the sagittal diameter of the foramen magnum, the length of the clivus, the length of the posterior part of the skull base, the basilar angle, the Boogard’s angle, the posterior angle of the base of the skull, angle of the cerebellar mantle, angle of inclination of the clivus, angle of inclination of the scales of the occipital bone and angle of convergence of the pyramids of the temporal bones. These parameters were determined on magnetic resonance tomograms in the sagittal projection on the median section and in the axial projection, on the section passing at the level of the internal auditory canals. The main group consisted of 15 patients who developed vascular complications after surgery, the second comparison group included 100 patients with uncomplicated postoperative course. The predominant head shapes according to the transverse-longitudinal index in both groups were brachycephalic (53.3 and 54%, respectively). There was no acrocephaly (high and narrow head forms) among patients with complications, while in the control group this type was registered in 12% of cases. Certain craniometric prerequisites for a complicated course of the postoperative period have been identified, allowing a more selective approach to the tactics of treating these patients. The risk group includes patients with large values ​​of the basilar angle and the angle of inclination of the scales of the occipital bone, having a narrower and elongated shape of the posterior cranial fossa.

Properties of different varieties of Maranta arundinacea’s starch.

The objective of this study was to analyze and compare arrowroot starch varieties of the "seta" (AS) and "redonda" (AR) varieties by assessing their chemical, morphological, rheological, structural and thermal characteristics, and verifying their applicability in the food industry. This research involved: proximal composition (moisture, ether extract, crude protein, crude fiber, ashes and glicidic fraction), infrared spectroscopy, scanning electron microscopy, determination of paste clarity and properties, X-ray diffraction, and thermal properties. The extracted starches have high purity, having low levels of the components analyzed in the proximal composition. The main chemical groups found in polysaccharides were determined in infrared spectroscopy. Both arrowroot starches exhibited fragility to high temperatures, lower resistance to dissociation of hydrogen bonds, and high final viscosity. The characteristic size of the starch granules is in the range of 8 μm to 45 μm, with a predominance of granules of approximately 30 μm, for both AR and AS, which can be considered large granules. The granules predominant geometric shapes are oval and ellipsoid Starches exhibited type-C crystallinity and initial, peak and final temperature values for gelatinization were well below the temperatures found in literature. The two starches exhibited potential for use in the industry of instant foods, breakfast cereals, infant food, meat products, and bakery products.

L1-norm based dynamic analysis of flexible multibody system modeled with trimmed isogeometry

Isogeometric analysis is an efficient method to accurately represent geometry and obtain accurate solutions, and can be utilized for dynamic analysis of flexible multibody systems. In this paper, l1 norm based dynamic analysis of flexible multibody system modeled with trimmed isogeometry is presented, in which, (1) the exact shape deformation of regular NURBS element after trimming is characterized by geometric transformation, (2) the l1 norm optimization is employed to select the predominant modal shapes for accurate dynamic analysis under rapidly changed loads, and (3) motion equations are sampled by considering the acceleration of control variables influence on control variables variation to obtain stable dynamic results. Finally, the presented approach is validated with three examples. The dynamic response results show that the trimmed isogeometric analysis can be employed to achieve considerable accuracy. As the continuity between NURBS elements increases from C0 to C1, the degree of freedom is reduced by 75%, and the computational time of l1 norm based dynamic analysis is about 35% of the full order modal shapes method. Furthermore, the proposed sampling method can be utilized to reduce the 33% sampling number compared with the Latin Hypercube sampling method.

Abundance and Characteristics of Microplastics Contaminating the Surface Water of the Inner Gulf of Thailand

Microplastics are pollutants with uncertain behaviors; they have mysterious impacts on marine environments. The present study is the first investigation of microplastic distribution in the surface water of the inner Gulf of Thailand. This study collected 100–200 L of surface water from 25 different sampling locations. Microplastics were visually counted and identified by Fourier-transform infrared microscopy. The results revealed that the average total abundance of microplastics (125–5000 µm) was 9.97 pieces/L (1.55 ng/L). Microplastics sized 125–300 µm were most abundant at all the sampling sites, accounting for 68% of the total microplastics. Fiber (35%) and fragment (34%) were the predominant microplastic shapes in the surface water. Polyethylene, polypropylene, and poly(ethylene propylene) accounted for the most prevalent polymer types. The present findings revealed that the inner Gulf of Thailand is moderately polluted by microplastics of different sizes, shapes, and types, which may pose a potential risk to coastal ecosystems.

System Identification of Mosques Resting on Soft Soil. The Case of the Suleiman Mosque in the Medieval City of Rhodes, Greece

The present study focuses on the dynamic system identification of the Suleiman Mosque minaret in the medieval city of Rhodes, Greece. Suleiman Mosque was built in 1522 at the site of the destroyed Christian Church of the Apostles. First, we performed sets of ambient vibration measurements at the minaret of the monument. Based on these data, we calculated the eigenproperties of the minaret. Next, we modeled the monument in three dimensions, using the finite element method. Six numerical models were considered. Model Ι is the simplest one (isolated, fixed base minaret). Model VI is the most complicated one (simulation of the whole mosque also considering soil–structure interaction and foundation flexibility). The calculated predominant periods and mode shapes of Models I–VI are validated against the microtremor field measurements, recorded on the minaret’s two floors and ground level. We elaborate on the reliability of finite element models for earthquake response evaluation, considering soil–structure interaction and foundation flexibility on the mode shape eigenfrequencies. Additionally, we discuss the seismic response of the minaret compared to the whole monument. We observed no significant difference in the first two modes of response, implying that the minaret’s dynamic behavior is slightly affected by the entire mosque’s presence.