Hasil untuk "Engineering (General). Civil engineering (General)"

Gengyang Li, Mason Peng, Qingguo Huang et al.

Per- and polyfluoroalkyl substances (PFAS) have drawn public concern recently due to their toxic properties and persistence in the environment, making it urgent to eliminate PFAS from contaminated water. Electrochemical oxidation (EO) has shown great promise for the destructive treatment of PFAS with direct electron transfer and hydroxyl radical (⋅OH)-mediated indirect reactions. One of the most popular electrodes is Magnéli phase titanium suboxides. However, the degradation mechanisms of PFAS are still unsure and are under investigation now. The main methodology is the first-principal density functional theory (DFT) computation, which is recently used to explore the degradation mechanisms and interpret by-product formation during PFAS mineralization. From the literature review, the main applications of DFT computation for studying PFAS degradation mechanisms by EO include bond dissociation energy, absorption energy, activation energy, and overpotential η for oxygen evolution reactions. The main degradation mechanisms and pathways of PFAS in the EO process include mass transfer, direct electron transfer, decarboxylation, peroxyl radical generation, hydroxylation, intramolecular rearrangement, and hydrolysis. In the recent 4 years, 11 papers performed DFT computation to explore the possible PFAS degradation mechanisms and pathways in the EO process. This paper’s objectives are to: 1) summarize the main degradation mechanisms of PFAS degradation in EO; 2) review the application of DFT computation for studying PFAS degradation mechanisms during EO; process; 3) review the possible degradation pathways of perfluorooctane sulfonoic acid (PFOS) and per-fluorooctanoic acid (PFOA) during EO process.

Tao Wang, Qi Luo, Fengyuan Cui et al.

Given the recent success of metasurfaces in free-space applications, these concepts can be leveraged to an even larger extent in on-chip waveguide systems. The in-plane diffractive metasurfaces enable the manipulation of guiding waves in the multimode regime with greater parallelism than conventional single-mode or few-mode waveguides, leading to exciting opportunities in signal processing and optical computing systems. Beam focusing is one of the basic functionalities of wavefront shaping, which can be implemented using phase gradient metalenses consisting of arrays of meta-atoms. The meta-atoms are mainly realized by etched trenches with varying lengths, which are assembled into a one-dimensional transmit array with a specific phase response. However, this kind of periodic arrayed structure has significantly limited design freedom compared to its free-space counterparts. Here, we propose a digital metalens that consists of a seamless array of pixelated unit cells, which are engineered via inverse design. In contrast to conventional focusing metalenses based on transmit arrays, highly functional digital metalenses have been demonstrated: (1) achromatic focusing lens; (2) extended depth of focus (EDOF) lens; (3) Airy beam lens. These devices were fabricated on a silicon photonic platform and characterized in near-infrared. The intersection of digital structures and algorithm-driven optimizations offers greater versatility for on-chip wavefront shaping.

Svetlana S. Konnova, Pavel A. Lepilin, Anastasia A. Zanishevskaya et al.

Biosensor technologies in medicine, as in many other areas, are replacing labor-intensive methods of monitoring human health. This paper presents the results of experimental studies on label-free sensors based on a hollow core microstructured optical waveguide (HC-MOW) for human blood serum analysis. The MOWs with a hollow core of 247.5 µm in diameter were manufactured and used in our work. These parameters allow the hollow core to be filled with high-viscosity solutions due to the capillary properties of the fiber. Calculations of the spectral properties of the HC-MOW fiber were carried out and experimentally confirmed. Twenty-one blood serum samples from volunteers were analyzed using standard photometry (commercial kits) and an experimental biosensor. The obtained transmission spectra were processed by the principal component analysis method and conclusions were drawn about the possibility of using this biosensor in point-of-care medicine. A significant difference was shown between the blood serum of healthy patients and patients with confirmed diagnoses and a long history of cardiovascular system abnormalities. Algorithms for spectra processing using the Origin program are presented.

Anna Wajs-Bonikowska, Ewa Maciejczyk, Łukasz Szoka et al.

This study investigates the essential oil (EO) isolated from the seeds and cones of Canadian hemlock (<i>Tsuga canadensis</i>), highlighting notable differences in their chemical composition and biological activities. The seed EO was uniquely dominated by oxygenated derivatives of monoterpene hydrocarbons, particularly bornyl acetate (40%), whereas the cone EO exhibited higher levels of monoterpene hydrocarbons such as α-pinene (23%), β-pinene (20%), and myrcene (23%). A significant finding was the strong cytotoxic activity of cone EO against melanoma cell lines, with IC₅₀ values as low as 0.104 ± 0.015 μL/mL, compared to the minimal effects of seed EO. Additionally, cone EO demonstrated stronger antimicrobial activity, with lower minimum inhibitory concentrations (MICs) against Gram-positive and Gram-negative bacteria, further highlighting its therapeutic potential. Lipophilic extracts from seeds were characterized by unsaturated fatty acids (linoleic, oleic, and sciadonic acids—specific to conifers) and bioactive molecules with high antioxidant and nutritional potential, such as β-tocopherol, β-sitosterol, and campestrol. These findings underscore the unique chemical composition of <i>T. canadensis</i> seed EO and its lipophilic extract, along with the potent cytotoxic and antimicrobial properties of cone EO, offering insights into their potential applications in natural products for pharmaceutical and therapeutic uses.

Marko Škrabić, Marija Majer, Zdravko Siketić et al.

Thin amorphous oxide films (a-SiO₂, a-Al₂O₃, a-MgO) were prepared by magnetron sputtering deposition. Their response to high-energy heavy ion beams (23 MeV I, 18 MeV Cu, 2.5 MeV Cu) and gamma-ray (1.25 MeV) irradiation was studied by elastic recoil detection analysis and infrared spectroscopy. It was established that their high radiation hardness is due to a high level of disorder, already present in as-prepared samples, so the high-energy heavy ion irradiation cannot change their structure much. In the case of a-SiO₂, this resulted in a completely different response to high-energy heavy ion irradiation found previously in thermally grown a-SiO₂. In the case of a-MgO, only gamma-ray irradiation was found to induce significant changes.

Alexandra COROIAN, Larisa IVASCU, Timea CISMA et al.

Romania's automotive sector is experiencing an evolution towards sustainable transport, with an increasing interest in incorporating solar power technology into vehicles. This article examines the present state of solar power use in Romania's automobile industry, including difficulties, possibilities, and prospects. The analysis looks at technology improvements, legislative applications, consumer preferences, and the carbon footprint of solar-powered cars in Romania.

José C. Matos, Vanni Nicoletti, Jakub Kralovanec et al.

Europe faces many problems connected to ageing infrastructure which was built in the second half of the 20th century. Bridges are one of the crucial elements of these infrastructures. In recent years, European countries have witnessed many failures of bridges across the continent. For example, the collapse of Viadotto Polcevera in Genoa caught the attention of society regarding its tragic consequences. Therefore, engineers must deal with the assessment of existing bridges which is essential for proper decision-making. Condition rating systems for bridges vary from country to country. Consequently, these differences in the methodology can lead to different conclusions related to the future service of assessed structures. For these reasons, this paper briefly describes condition rating systems for road bridges in Italy, Slovakia, and Portugal and defines the differences in the methodology. Subsequently, the obtained conclusions are compared and discussed. The aim of the paper is to encourage standardization in the assessment of bridge health conditions within European countries, highlighting the differences in the current systems adopted by various countries.

Alba de las Heras, Ana I. Gómez-Varela, María-Baralida Tomás et al.

The COVID pandemic is forcing the renewal of scientific conferences, offering opportunities to introduce technological and inclusive developments. Our analysis focuses on the implementation of inclusive practices for female and early-career researchers in a virtual scientific conference. This organization approach was applied in the XIII Spanish Optical Meeting (RNO2021), which was also characterized by avatars interacting in an online metaverse. The effectiveness of inclusive policies and novel technological tools was evaluated using the participation data and a post-conference survey. Our study reveals the high impact of inclusive actions and a strong interest in the scientific community to explore conference advances.

Bumin Meng, Zhengzhao Zhou, Congyue Zhang et al.

ABSTRACT: The brake-by-wire (BBW) system is an essential part of the intelligent electric vehicle, which is determination of the braking safety and recovery efficiency. To design a safe and efficient booster motor, the design of booster motor for BBW system is discussed in this paper. Through comparative analysis, experimental simulation and assessment argument, the scheme of designing a booster motor for brake-by-wire system is completely described. First, the mainstream structure of the BBW system and the main challenges it faces in the assisted motor are discussed. Second, comparing the motors of different types and structures, the motor body and control system scheme suitable for the characteristics of the booster motor system are determined. Then, through the simulation analysis of the ansoft and matlab, the optimization scheme of the motor and performance improvement are proposed. Further, through the actual design of a set of the booster motor system, the safe and efficient motor designing are verified, and the problems involving functional safety are discussed. Finally, focus on the problem while simulation and experiment, some important countermeasures to improve current technology and prospect of in-depth study are pointed out.

Mingli Huang, Xiayi Yao, Zhongsheng Tan et al.

Building deep shafts in water-rich granite formations with large fissures has difficulties, such as high-water pressure and high construction risks, and is prone to water inrush and shaft flooding. This paper relies on the No. 1 vertical auxiliary shaft project of Gaoligongshan tunnel and obtains the uneven distribution of water pressure on the outside of the lining in the horizontal direction through on-site monitoring data. In order to explain this phenomenon, based on the statistical parameters of actual fractures in the field and the Monte Carlo method, the DFN built in FLAC3D6.0 is used to generate a discrete fracture network, and a dual medium model, considering the distribution of large fractures, is established. The reason for the uneven distribution of water pressure is obtained through research: the large fissures in the surrounding rock make the hydraulic conductivity of each part of the stone body formed after grouting of the surrounding rock different. This results in different osmotic pressures from the hydrostatic pressure outside the grouting ring to the outside of the lining through the grouting ring. Based on the distribution characteristics of water pressure outside the lining, the safety of the lining under non-uniform pressure is studied. The lining safety factor is defined as the ratio of the lining’s normal service limit state load to the actual load. The normal service limit state load is the load when the RFPA software is used to establish a load-structure model to simulate the load when the lining has obvious cracks under the action of external load; the actual load is the monitoring load. The new method and mine design code method are used to evaluate the lining safety and make a comparative analysis. The results show that the new method can effectively calculate the lining safety factor and has a larger safety reserve.

Restu Nur Hakim

Unit jasa keuangan syariah adalah unit usaha pada koperasi yang kegiatan usahanya bergerak di bidang pembiayaan, investasi, dan simpanan sesuai dengan pola bagi hasil (syariah). Penelitian ini bertujuan untuk membuat sebuah sistem pendukung keputusan menentukan penerimaan pembiayaan akad qordh menggunakan metode Analitycal Hierarchy Process (AHP) yang digunakan untuk menentukan bobot kriteria dan metode Weighted Product (WP) digunakan untuk menentukan ranking penerima pembiayaan akad qordh. Berdasarkan hasil perhitungan AHP dan WP, didapatkan hasil alternatif yang direkomendasikan pertama mendapat pembiayaan akad qordh adalah alternatif 7 dengan nilai V_7 yaitu 0,159, diikuti oleh alternatif 3 dengan nilai V_3 yaitu 0,109, alternatif 1 dengan nilai V_1 yaitu 0,105, alternatif 6 dengan nilai V_6 yaitu 0,098, alternatif 8 dengan nilai V_8 yaitu 0,096, alternatif 9 dengan nilai V_9 yaitu 0,093, alternatif 4 dengan nilai V_4 yaitu 0,082, alternatif 5 dengan nilai V_5 yaitu 0,081, alternatif 2 dengan nilai V_2 yaitu 0,061, alternatif 10 dengan nilai V_10 yaitu 0,057, dan yang

Xin Zhang, Qianqian Fu, Jianping Ge

An invisible photonic crystal (PC) pattern encrypted at the dry state and decrypted by solvent is a new anticounterfeiting material system, but its diversity and complexity in response are still required to be increased to enhance the anticounterfeiting effect. Herein, a triple‐state invisible pattern encrypted in hollow‐silica/polyurethane (h‐SiO2/PU) film with two decryption mechanisms is developed based on the asymmetric solvent response of h‐SiO2/PU with different SiO2 shell thicknesses. The pattern is printed via etching SiO2 shell in the designed region, which creates an etched “pattern” containing thin‐shell h‐SiO2 particles and an unetched “background” containing thick‐shell particles. Different from the traditional invisible PC patterns, the current system possesses triple states, including a “dry” invisible state composed of two close inverse opal structures, a “wet” invisible state composed of inverse opals filled with water, and an ethanol‐soaking visible state due to the prevention of solvent diffusion by the thicker shell. The invisible patterns are reversibly and randomly switched among these three states, which suggest that they are decrypted from the dry invisible state through selective solvent infiltration or from the wet invisible state through selective extraction. Such increased diversity and complexity make this invisible PC pattern ideal material for anticounterfeiting applications.

Chao Wang, Xiaoyi Chen, Jiandong Zhang et al.

This paper is aimed at the inverted arch support instability of track roadway with mining level +1100 m in Liuyuanzi Coal Mine. By means of field investigation, theoretical analysis, numerical calculation, and engineering practice, the instability reasons of inverted arch structure are expounded, the mechanical mechanism of instability of inverted arch structure is revealed, and the “sliding-rotating beam” for the instability of inverted arch structure is put forward. Based on Fenner’s formula and mechanics principle, the equilibrium equation of “sliding-rotating beam” is given. The results show the following: Firstly, the insufficient stiffness at the joint of the inverted arch structure and the U-shaped steel support on the floor is the key reason for the floor instability. Secondly, when the action stress of the “sliding-rotating beam” is less than the critical value, three kinds of instability modes of the inverted arch structure may occur, that is, sliding upward, rotating upward, or sliding-rotating upward. Each instability criterion and critical value are also different. Considering the axisymmetric condition, the critical value calculation formula of the three modes can be simplified into one formula. Thirdly, the equivalent friction factor restricts the stability of the “sliding-rotating beam,” and there is a “breaking point.” The relationship between the equivalent friction factor and the action stress of the “sliding-rotating beam” is “class hyperbola.” When the equivalent friction factor is greater than the “breaking point value,” the “sliding-rotating beam” may remain stable. Moreover, with the increase of equivalent friction factor, the action stress required for the stability of the “sliding-rotating beam” is smaller, and it tends to be more stable. The breaking point value of equivalent friction factor is 18.6. Finally, 36U-shaped steel round frame with bolt-mesh-shotcrete-combined support is applied to improve the equivalent friction factor and the foot stiffness of U-shaped support in roadway. After two months of on-site implementation, the floor heave was reduced by 69.1%. In conclusion, the theoretical analysis is correct and the control method is effective.

B. Chen, J. Craven, Qian Wang et al.

Vyacheslav Vishnevetskiy, Vladislav Popruzhniy

The aim of this study was to establish the correlation between natural water pollutions and the prevalence of heart diseases. We analyzed the data from the 2014 Federal Service Report on the state of sanitary and epidemiological welfare of the population. The correlation analysis of data on mortality and primary morbidity of the population was carried out, the correlation between the quality of natural water and cardiovascular diseases of the population was established. The complex method of water quality assessment according to the data of hydrochemical monitoring of the Azov Sea and rivers flowing into it were used in the investigation, the influence of the main pollutants such as copper and manganese on the dynamics of cardiovascular diseases according to mortality and primary morbidity for the population of Taganrog was considered. As conclusion we can state that statistical association between water intake and heart diseases exists in the region of analysis. However, further studies on water intake are needed to confirm our findings.

Jiress Joseph Flórez-Santiago, Carlos David Grande-Tovar, Carlos Enrique Díaz-Uribe

Recientes investigaciones demuestran la importancia de los extractos de origen vegetal como potentes antioxidantes, debido a la presencia de componentes químicamente activos, como los polifenoles, antocianinas, flavonoides, entre otros. Esta sinergia de los componentes se convierte en una posible alternativa frente al uso de antioxidantes de origen sintético. En este trabajo la cáscara de la fruta Syzygium cumini fue utilizada para determinar la actividad antioxidante frente al oxígeno singulete. El extracto mostró cantidades apreciables de grupos fenólicos (alrededor de 8,55 AGE mg/g peso fruta). La caracterización por HPLC-DAD muestra por lo menos 3 antocianinasde mayor abundancia relativa (la malvidina 3,5-diglucósido, la delfinidina 3,5- diglucósido y la petunidina 3,5-diglucósido). El porcentaje de desactivación del oxígeno singulete fue determinado a diferentes concentraciones del extracto etanólico, encontrándose un valor del 60% a una concentración 0.39 mg/mL.

Iliescu Dragoș, Gheorghe Marian

Information quantity subject is approached in this paperwork, considering the specific domain of nonconforming product management as information source. This work represents a case study. Raw data were gathered from a heavy industrial works company, information extraction and knowledge formation being considered herein. Involved method for information quantity estimation is based on Shannon entropy formula. Information and entropy spectrum are decomposed and analysed for extraction of specific information and knowledge-that formation. The result of the entropy analysis point out the information needed to be acquired by the involved organisation, this being presented as a specific knowledge type.

Ning Liu

In this study, the concept of Pan-River-Basin (PRB) for water resource management is proposed with a discussion on the emergence, concept, and application of PRB. The formation and application of PRB is also discussed, including perspectives on the river contribution rates, harmonious levels of watershed systems, and water resource availability in PRB system. Understanding PRB is helpful for reconsidering river development and categorizing river studies by the influences from human projects. The sustainable development of water resources and the harmonization between humans and rivers also requires PRB.

George P. Kouropoulos

At this study an attempt for the theoretical approach of the Re ynolds number effect of air flow to the particle collection efficiency of a fibrous fil ter with cylindrical section will be made. Initially, a report of the air filtration models to fibrous filter media will be presented along with an explanation of both the parameters and the physical quantities which govern the air filtration process. Furthermore, the resul ting equation from the mathematical model will be applied to a real filter medium and the characteristic curves of filter efficiency will be drawn. The change of a filter medi um efficiency with regard to the Reynolds number of air flow that passes through the filt er, derived from the curves, will be studied. The general conclusion that we have is that as the Reynolds number of filtered air increases, the collection efficiency of the filter decreases.

Y. Xue, T. Fung, J. Tsou

Urban warming is sensitive to the nature (thermal properties, including albedo, water content, heat capacity and thermal conductivity) and the placement (surface geometry or urban topography) of urban surface. In the literature the spatial dependence and heterogeneity of urban thermal landscape is widely observed based on thermal infrared remote sensing within the urban environment. Urban surface warming is conceived as a big contribution to urban warming, the study of urban surface warming possesses significant meaning for probing into the problem of urban warming.The urban thermal landscape study takes advantage of the continuous surface derived from thermal infrared remote sensing at the landscape scale, the detailed variation of local surface temperature can be measured and analyzed through the systematic investigation. At the same time urban environmental factors can be quantified with remote sensing and GIS techniques. This enables a systematic investigation of urban thermal landscape with a link to be established between local environmental setting and surface temperature variation. The goal of this research is utilizing Geographically Weighted Regression (GWR) to analyze the spatial relationship between urban form and surface temperature variation in order to clarify the local effects on surface warming, moreover to reveal the possible dynamics in the local influences of environmental indicators on the variation of local surface temperature across space and time. In this research, GWR analysis proved that the spatial variation in relationships between environmental setting and surface temperature was significant with Monte Carlo significance test and distinctive in day-night change. Comparatively, GWR facilitated the site specific investigation based on local statistical technique. The inference based on GWR model provided enriched information regarding the spatial variation of local environment effect on surface temperature variation which global model cannot approach.