Search results for: laboratory investigations

Authors: Shahrad Ebrahimzadeh

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Nowadays, the main efforts of the researchers aim to constantly evolve new, optimized and efficient construction materials and methods related to reinforced concrete beams. Due to the fewer applied materials and offering a higher structural efficiency compared to solid concrete beams with the same concrete area, hollow reinforced concrete beams (HRCB) internally reinforced with steel rebars have been employed extensively for bridge structural members and high-rise buildings. Many experimental studies have been conducted to investigate the behavior of hollow beams subjected to bending loading and found that the structural performance of HRCBs is critically affected by many design parameters. While the proper design of the HRCBs demonstrated comparable behavior to solid sections, inappropriate design leads beams to be extremely prone to brittle failure. Another potential issue that needs to be further investigated is the replacement of steel bars with suitable materials due to their susceptibility to corrosion. Hence, to develop a reliable construction system, the application of GFRP bars as a non-corroding material has been utilized. Furthermore, this study aims to critically review the different design parameters that affect the flexural performance of the HRCBs and recognize the gaps of knowledge in the better design and more effective use of this construction system.

Keywords: design parameters, experimental investigations, hollow reinforced concrete beams, steel, GFRP, flexural strength

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Authors: M. M. Ali, Ahmed Al- Ani, Derek Eamus, Daniel K. Y. Tan

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In this glasshouse study, we developed the new image-based non-destructive technique for detecting leaf P status of different crops such as cotton, tomato and lettuce. Plants were allowed to grow on nutrient media containing different P concentrations, i.e. 0%, 50% and 100% of recommended P concentration (P0 = no P, L; P1 = 2.5 mL 10 L-1 of P and P2 = 5 mL 10 L-1 of P as NaH2PO4). After 10 weeks of growth, plants were harvested and data on leaf P contents were collected using the standard destructive laboratory method and at the same time leaf images were collected by a handheld crop image sensor. We calculated leaf area, leaf perimeter and RGB (red, green and blue) values of these images. This data was further used in the linear discriminant analysis (LDA) to estimate leaf P contents, which successfully classified these plants on the basis of leaf P contents. The data indicated that P deficiency in crop plants can be predicted using the image and morphological data. Our proposed non-destructive imaging method is precise in estimating P requirements of different crop species.

Keywords: image-based techniques, leaf area, leaf P contents, linear discriminant analysis

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Authors: H. Al-Baghli

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Laboratory trial results of mixing crumb rubber produced from discarded tires with 60/70 pen grade Kuwaiti bitumen are presented on this paper. PG grading and multiple stress creep recovery tests were conducted on Kuwaiti bitumen blended with 15% and 18% crumb rubber at temperatures ranging from 40 to 70 °C. The results from elastic recovery and non-recoverable creep presented optimum performance at 18% rubber content. The optimum rubberized-bitumen mix was next transformed into a pelletized form (PelletPave^®), and was used as a partial replacement to the conventional bitumen in the manufacture of continuously graded hot mix asphalts at a number of binder contents. The trialed PelletPave^® contents were at 2.5%, 3.0%, and 3.5% by mass of asphalt mix. In this investigation, it was not possible to utilize the results of standard Marshall method of mix design (i.e. volumetric, stability and flow tests) and subsequently additional assessment of mix compactability was carried out using gyratory compactor in order to determine the optimum PelletPave^® and total binder contents.

Keywords: crumb rubber, Marshall mix design, PG grading, rubberized-bitumen

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Authors: Apolinar Picado, Ronald Solís, Rafael Gamero

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The thin-layer drying characteristics of instant coffee solution were investigated in a laboratory tunnel dryer. Drying experiments were carried out at three temperatures (80, 100 and 120 °C) and an air velocity of 1.2 m/s. Drying experimental data obtained are fitted to six (6) thin-layer drying models using the non-linear least squares regression analysis. The acceptability of the thin-layer drying model has been based on a value of the correlation coefficient that should be close to one, and low values for root mean square error (RMSE) and chi-square (x²). According to this evaluation, the most suitable model for describing drying process of thin-layer instant coffee solution is the Page model. Further, the effective moisture diffusivity and the activation energy were computed employing the drying experimental data. The effective moisture diffusivity values varied from 1.6133 × 10⁻⁹ to 1.6224 × 10⁻⁹ m²/s over the temperature range studied and the activation energy was estimated to be 162.62 J/mol.

Keywords: activation energy, diffusivity, instant coffee, thin-layer models

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Authors: S. Kumar, R. Sultana

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This study was conducted to evaluate the effect of Aspergillus species on acridid populations which are major agricultural pests of rice, sugarcane, wheat, maize and fodder crops in Pakistan. Three and replicates i.e. Aspergillus flavus, A. fumigatus and A. niger, excluding the control, were held under laboratory conditions. It was observed that consumption faecal production of acridids was significantly reduced after the pathogenic application of Aspergillus. In the control replicate, the mortality ratio for stage (N₄-N₆) was maximum on day 2^nd i.e. [F_10.7 = 18.33, P < 0.05] followed by [F_4.20 = 07.85, P < 0.05] and [F_3.77 = 06.11, P < 0.05] on 4^th and 3^rd day, respectively. Similarly, it was a minimum i.e. [F_0.48 = 84.65, P < 0.05] on the 1^st day. It was also noted that faecal production of Acridid nymphs was not significantly affected when treated with conidial concentration in H₂O formulation; however, it was significantly reduced after the contamination with conidial concentration in oil. The high morality of acridids after contamination of Aspergillus supports their use as bio-control agent for reducing pest population. The present study recommends that exploration and screening must be conducted to provide additional pathogens for evaluation as potential biological control against grasshoppers and locusts.

Keywords: acridid, agriculture, formulation, grasshoppers

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Authors: Zahra Azizi, Ashkan Karbasi, Farzin Firouzian, Sara Soleimani Asl, Akram Ranjbar

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Background: One of the most often used herbicides in agriculture is paraquat (PQ), which is very harmful to both people and animals. Chitosan is a well-known, non-toxic polymer commonly used in preparing particles via ionotropic gelation facilitated by negatively charged agents such as sodium alginate. This study aimed to compare the effects of PQ and nanoparaquat (PQNPs) on liver function in male rats. Materials & Methods: Rats were exposed to PQ & PQNPs (4 mg/kg/day, intraperitoneally) for seven days. Then, rats were anesthetized, and serum and liver samples were collected. Later, enzymatic activities such as alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP) in serum and oxidative stress biomarkers such as lipid peroxidation (LPO), total antioxidant capacity (TAC) and total thiol groups (TTG) levels in liver tissue were measured by colorimetric methods. Also, histological changes in the liver were evaluated. Results: PQ altered the levels of ALT, AST, and ALP while inducing oxidative stress in the liver. Additionally, liver homogenates with PQ exposure had challenged LPO, TAC, and TTG levels. The severe liver damage is indicated by a significant increase in the enzyme activity of AST, ALT, and ALP in serum. According to the results of the current study, PQNPs, as compared to PQ and the control group, lowered ALT, AST, ALP, and LPO levels while increasing TAC and TTG levels. Conclusion: According to biochemical and histological investigations, PQ loaded in chitosan-alginate particles is more efficient than free PQ at reducing liver toxicity.

Keywords: paraquat, paraquat nanoparticles, liver, oxidative stress

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Authors: Huy Q. Tran, Jungwon Huh, Kiseok Kwak, Choonghyun Kang

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Infrared thermography (IRT) technique has been proven to be a good method for nondestructive evaluation of concrete material. In the building, a broad range of applications has been used such as subsurface defect inspection, energy loss, and moisture detection. The purpose of this research is to consider the qualitative and quantitative performance of reinforced concrete deteriorations using active infrared thermography technique. An experiment of three different heating regimes was conducted on a concrete slab in the laboratory. The thermal characteristics of the IRT method, i.e., absolute contrast and observation time, are investigated. A linear relationship between the observation time and the real depth was established with a well linear regression R-squared of 0.931. The results showed that the absolute contrast above defective area increases with the rise of the size of delamination and the heating time. In addition, the depth of delamination can be predicted by using the proposal relationship of this study.

Keywords: concrete building, infrared thermography, nondestructive evaluation, subsurface delamination

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Authors: Mallikarjun Warad, C. M. Kalleshwaraswamy, P. R. Shashank

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Studies were conducted to record the occurrence of different species of hairy caterpillar on different host plants in and around Shivamogga, Karnataka, India. Twelve genera of hairy caterpillars belonging to Arctiinae and Lymantriinae were recorded on different host plants and reared to adults in laboratory on their respective hosts. The Porthesia sp. feed on castor, Creatonotus gangis on cocoa, Perina nuda on fig, Pericalia ricini on pigeon pea, Utetheisa pulchella on sunhemp and Euproctis sp. on paddy and banana. Illustrations of immature and adults were made to associate them. Along with this, light traps were also set during the rainy season, to capture adults of hairy caterpillars. An illustrated identification key was provided for easy and accurate identification of adult of hairy caterpillars based on their morphological (male genitalial) characters. The study through a light on the existence of sexual dimorphism, polyphagous nature and diapause are the major hindrance in taxonomic identification. Hence, attempts were made to address these issues in the study.

Keywords: Erebidae, hairy caterpillars, male genitalia, taxonomy

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Authors: Rajani S. Pujar, Pandurangarao N. Kulkarni

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Increased temporal masking affects the speech perception in persons with sensorineural hearing impairment especially under adverse listening conditions. This paper presents a cascaded scheme, which employs a noise reduction algorithm as well as temporal splitting of the speech signal. Earlier investigations have shown that by splitting the speech temporally and presenting alternate segments to the two ears help in reducing the effect of temporal masking. In this technique, the speech signal is processed by two fading functions, complementary to each other, and presented to left and right ears for binaural dichotic presentation. In the present study, half cosine signal is used as a fading function with crossover gain of 6 dB for the perceptual balance of loudness. Temporal splitting is combined with noise reduction algorithm to improve speech perception in the background noise. Two noise reduction schemes, namely spectral subtraction and Wiener filter are used. Listening tests were conducted on six normal-hearing subjects, with sensorineural loss simulated by adding broadband noise to the speech signal at different signal-to-noise ratios (∞, 3, 0, and -3 dB). Objective evaluation using PESQ was also carried out. The MOS score for VCV syllable /asha/ for SNR values of ∞, 3, 0, and -3 dB were 5, 4.46, 4.4 and 4.05 respectively, while the corresponding MOS scores for unprocessed speech were 5, 1.2, 0.9 and 0.65, indicating significant improvement in the perceived speech quality for the proposed scheme compared to the unprocessed speech.

Keywords: MOS, PESQ, spectral subtraction, temporal splitting, wiener filter

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Authors: F. Onyango, Salim R. Wanjala, M. Ndege, L. Masu

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Asphalt concrete pavements have a short life cycle, failing mainly due to temperature changes, traffic loading and ageing. Modified asphalt mixtures provide the technology to produce a bituminous binder with improved viscoelastic properties which remain in balance over a wider temperature range and loading conditions. In this research, 60/70 penetration grade asphalt binder was modified by adding 2, 4, 6, 8, and 10 percent by weight of asphalt binder following the wet process and the mineral aggregate was modified by adding 1, 2, 3, 4, and 5 percent crumb rubber by volume of the mineral aggregate following the dry process. The LDPE modified asphalt binder Rheological properties were evaluated. The laboratory results showed an increase in viscosity, softening point and stiffness of the binder. The modified asphalt was then used in preparing asphalt mixtures by Marshall Mix design procedure. The Marshall stability values for mixes containing 2% crumb rubber and 4% LDPE were found to be 30% higher than the conventional asphalt concrete mix.

Keywords: crumb rubber, dry process, hot mix asphalt, wet process

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Authors: Belkheir Noura, Rabah Kerfah, Boumehani Abdellah

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The influence of solidity variations on the aerodynamic performance of H type vertical axis wind turbine is studied in this paper. The wind turbine model used in this paper is the three-blade wind turbine with the symmetrical airfoil, NACA0021. The length of the chord is 0.265m. Numerical investigations were implemented for the different solidity by changing the radius and blade number. A two-dimensional model of the wind turbine is employed. The approach a Reynolds-Averaged Navier–Stokes equations, completed by the K- ώ SST turbulence model, is used. Motion mesh model capability of a computational fluid dynamics (CFD) solver is used. For each value of the solidity, the aerodynamics performances and the characteristics of the flow field are studied at several values of the tip speed ratio, λ = 0.5 to λ = 3, with an incoming wind speed of 8 m/s. The results show that increasing the number of blades will reduce the maximum value of the power coefficient of the wind turbine. Also, for the VAWT with a lower solidity can obtain the maximum Cp at a high tip speed ratio. The effects of changing the radius and blade number on aerodynamic performance are almost the same. Finally, for the validation, experimental data from the literature and computational results were compared. In conclusion, to study the influence of the solidity in the performances of the wind turbine is to provide the reference for the design of H type vertical axis wind turbines.

Keywords: wind energy, darrieus h type vertical axis wind turbine, computational fluid dynamic, solidity

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Authors: Mahshid Rezaei, Zahra Tajari, Zahra Esmaeily, Atefeh Eyvazkhani, Shahrzad Daei, Marjan Mansouri Dara, Mohaddesh Rezaei, Abolghassem Djazayeri, Ahmadreza Dorosti Motlagh

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Background: Musculoskeletal pain is one of the most prevalent symptoms in elderly age. Nutrition and diet are considered important underlying factors that could affect chronic musculoskeletal pain. The purpose of this study was to identify the relationship between empirical dietary inflammatory patterns (EDII) and musculoskeletal pain. Method: In this cross-sectional study, 213 elderly individuals were selected from several health centers. The usual dietary intake was evaluated by a valid and reliable 147-items food frequency questionnaire (FFQ). To measure the intensity of pain, Visual Analogue Scale (VAS) was used. Multiple Linear Regression was applied to assess the association between EDII and musculoskeletal pain. Results: The results of multiple linear regression analysis indicate that a higher EDII score was associated with higher musculoskeletal pain (β= 0.21: 95% CI: 0.24-1.87: P= 0.003). These results stayed significant even after adjusting for covariates such as sex, marital status, height, family number, sleep, BMI, physical activity duration, waist circumference, protector, and medication use (β= 0.16: 95% CI: 0.11-1.04: P= 0.02). Conclusion: Study findings indicated that higher inflammation of diet might have a direct association with musculoskeletal pains in elderlies. However, further investigations are required to confirm these findings.

Keywords: musculoskeletal pain, empirical dietary inflammatory pattern, elderlies, dietary pattern

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Authors: Boma Nellie S, Nambiar Ritu, K. Kanchanmala, T. Rashida, Israell Imelda, Moul Khusnud, Michael Marina

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Gestational diabetes (GDM) imparts an increased life long risk of developing Type 2 Diabetes Mellitus (T2DM) and cardiovascular disease in women. Once diagnosed with GDM women have up to 74% increased cumulative risk developing T2DM in 10-15 years. Identifying women at increased risk of developing T2DM and offering them pharmacological and lifestyle management interventions will delay or eliminate the development of diabetes in this population. While ADA recommends that all gestational diabetics be offered postnatal screening, worldwide the screening rates from 35-75% and Al Rahba Hospital with a robust universal antenatal screening program for GDM was at a dismal 9% in 2011. A multidisciplinary team was put together involving OB/Gyn Physicians, Midwives, Nurses (ward and OPD) Diabetic Educators, Dietitians, Medical Records, Laboratory & IT with the implementation of multiple strategies to increase the uptake of postpartum screening of the gestational diabetic.

Keywords: GDM, postnatal screening, preventing type 2 diabetes, lifestyle management

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Authors: Mohamed Benaicha, Mahdi Allam

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A new two stage electrochemical process as a safe, large area and low processing cost technique for the production of semi-conducting CuInSe2 (CIS) thin films is studied. CuIn precursors were first potentiostatically electrodeposited onto molybdenum substrates from an acidic thiocyanate electrolyte. In a second stage, the prepared metallic CuIn layers were used as substrate in the selenium electrochemical deposition system and subjected to a thermal treatment in vacuum atmosphere, to eliminate binary phase formation by reaction of the Cu2-x Se and InxSey selenides, leading to the formation of CuInSe2 thin film. Electrochemical selenization from aqueous electrolyte is introduced as an alternative to toxic and hazardous H2Se or Se vapor phase selenization used in physical techniques. In this study, the influence of film deposition parameters such as bath composition, temperature and potential on film properties was studied. The electrochemical, morphological, structural and compositional properties of electrodeposited thin films were characterized using various techniques. Results of Cyclic and Stripping-Cyclic Voltammetry (CV, SCV), Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray microanalysis (EDX) investigations revealed good reproducibility and homogeneity of the film composition. Thereby optimal technological parameters for the electrochemical production of CuIn, Se as precursors for CuInSe2 thin layers are determined.

Keywords: photovoltaic, CIGS, copper alloys, electrodeposition, thin films

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Authors: S. Patel, T. Mitra, R. Dubey, J. Keller

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In the present investigations, an attempt has been made to study the charge storage mechanism and mechanism for the flow of transient charging and discharging current in an amorphous polymer (Polysulfone) (PSF) and a semi-crystalline polar Polyvinylidene fluoride (PVDF) blends in ratio PSF: PVDF: 80:20;85:15;90:10 and 95:05 at various poling temperatures (i.e. 60, 75, 90 and 1150C) and with field strength (100, 150, 200 and 250kVcm⁻¹). Thermally stimulated depolarizing current TSDC thermograms for (Polysulfone (PSF) and Polyvinylidene fluoride (PVDF) Blends sample have been obtained under different polarizing conditions. Peaks are found at high-temperature side. The variation of structure on blending and poling condition affects the magnitude of TSDC. The activation energy values have been calculated using the initial rise method of Garlick and Gibson. The transient current with the similar polarizing condition has been investigated over a period of 3X10³ sec. The observed characteristics obey Curie-Von Schweidler law in the studied temperature range. The charging current versus polarizing temperature curves at a constant time, i.e., isochronal current characteristics were studied and the activation energies were calculated. The activation energy in transient thermograms calculated by different methods is in good agreement with the values obtained from TSDC studies.

Keywords: activation energy, polysulfone (PSF), polyvinylidenefluoride (PVDF), thermally stimulated depolarizing current (TSDC)

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Authors: Jayson G. Balansag

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An integrated biology and chemistry (iBC) course for freshmen college students was developed in University of Delaware. This course will prepare students to (1) become interdisciplinary thinkers in the field of biology and (2) collaboratively work with others from multiple disciplines in the future. This paper documents and describes the implementation of the course. The information gathered from reading literature, classroom observations, and interviews were used to carry out the purpose of this paper. The major goal of the iBC course is to align the concepts between Biology and Chemistry, so that students can draw science concepts from both disciplines which they can apply in their interdisciplinary researches. This course is offered every fall and spring semesters of each school year. Students enrolled in Biology are also enrolled in Chemistry during the same semester. The iBC is composed of lectures, laboratories, studio sessions, and workshops and is taught by the faculty from the biology and chemistry departments. In addition, the preceptors, graduate teaching assistants, and studio fellows facilitate the laboratory and studio sessions. These roles are interdependent with each other. The iBC can be used as a model for higher education institutions who wish to implement an integrated biology course.

Keywords: integrated biology and chemistry, integration, interdisciplinary research, new biology, undergraduate science education

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Authors: H. Barati, M. Wu, A. Kharicha, A. Ludwig

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A transient model for nozzle clogging has been developed and successfully validated against a laboratory experiment. Key steps of clogging are considered: transport of particles by turbulent flow towards the nozzle wall; interactions between fluid flow and nozzle wall, and the adhesion of the particle on the wall; the growth of the clog layer and its interaction with the flow. The current paper is to investigate the mesh (size and type) sensitivity of the model in both two and three dimensions. It is found that the algorithm for clog growth alone excluding the flow effect is insensitive to the mesh type and size, but the calculation including flow becomes sensitive to the mesh quality. The use of 2D meshes leads to overestimation of the clog growth because the 3D nature of flow in the boundary layer cannot be properly solved by 2D calculation. 3D simulation with tetrahedron mesh can also lead to an error estimation of the clog growth. A mesh-independent result can be achieved with hexahedral mesh, or at least with triangular prism (inflation layer) for near-wall regions.

Keywords: clogging, continuous casting, inclusion, simulation, submerged entry nozzle

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Authors: Preeti Aghalayam, Jay Shah

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Underground coal gasification (UCG) is the in-situ gasification of unmineable coals to produce syngas. In UCG, gasifying agents are injected into the coal seam, and a reactive cavity is formed due to coal consumption. The cavity formed is typically hemispherical, and this report consists of the MATLAB model of the UCG cavity to predict the composition of the output gases. There are seven radial and two time-variant ODEs. A MATLAB solver (ode15s) is used to solve the radial ODEs from the above equations. Two for-loops are implemented in the model, i.e., one for time variations and another for radial variation. In the time loop, the radial odes are solved using the MATLAB solver. The radial loop is nested inside the time loop, and the density odes are numerically solved using the Euler method. The model is validated by comparing it with the literature results of laboratory-scale experiments. The model predicts the radial and time variation of the product gases inside the cavity.

Keywords: gasification agent, MATLAB model, syngas, underground coal gasification (UCG)

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Authors: Stuart Bradley, Mathew Legg, Lilyan Panton

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Ultrasonic remote sensing is a useful tool for assessing the interior structure of complex targets. For these methods, significantly enhanced spatial resolution is obtained if the pulse is coded, for example using a linearly changing frequency during the pulse duration. Such pulses have a time-dependent spectral structure. Interpretation of the backscatter from targets is, therefore, complicated if the scattering is frequency-dependent. While analytic models are well established for steady sinusoidal excitations applied to simple shapes such as spheres, such models do not generally exist for temporally evolving excitations. Therefore, models are developed in the current paper for handling such signals so that the properties of the targets can be quantitatively evaluated while maintaining very high spatial resolution. Laboratory measurements on simple shapes are used to confirm the validity of the models.

Keywords: linear FM chirp, time-dependent acoustic scattering, ultrasonic remote sensing, ultrasonic scattering

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Authors: Janusz Kwaśniewski, Ireneusz Dominik, Krzysztof Lalik

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The knowledge about rock layers thickness, especially above drilled mining pavements are crucial for workers safety. The measuring systems used nowadays are generally imperfect and there is a strong demand for improvement. The application of a new type of a measurement system called Self-Excited Acoustical System is presented in the paper. The system was applied until now to monitor stress changes in metal and concrete constructions. The change in measurement methodology resulted in possibility of measuring the thickness of the rocks above the tunnels as well as thickness of a singular rock layer. The idea is to find two resonance frequencies of the self-exited system, which consists of a vibration exciter and vibration receiver placed at a distance, which are coupled with a proper power amplifier, and which operate in a closed loop with a positive feedback. The resonance with the higher amplitude determines thickness of the whole rock, whereas the lower amplitude resonance indicates thickness of a singular layer. The results of the laboratory tests conducted on a group of different rock materials are also presented.

Keywords: auto-oscillator, non-destructive testing, rock thickness measurement, geotechnic

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Authors: David Nantes, George Gilbert

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There are a lot of risks that might crop up as a tunneling project develops, and it's crucial to be aware of them. Due to the unexpected nature of tunneling projects and the interconnectedness of risk occurrences, the risk assessment approach presents a significant challenge. The purpose of this study is to provide a hybrid FDEMATEL-ANP model to help prioritize risks during tunnel construction projects. The ambiguity in expert judgments and the relative severity of interdependencies across risk occurrences are both taken into consideration by this model, thanks to the Fuzzy Decision-Making Trial and Evaluation Laboratory (FDEMATEL). The Analytic Network Process (ANP) method is used to rank priorities and assess project risks. The authors provide a case study of a subway tunneling construction project to back up the validity of their methodology. The results showed that the proposed method successfully isolated key risk factors and elucidated their interplay in the case study. The proposed method has the potential to become a helpful resource for evaluating dangers associated with tunnel construction projects.

Keywords: risk, prioritization, FDEMATEL, ANP, tunneling construction projects

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Authors: Seyyed Mohammad Amin Mousavi Sagharchi, Alireza Mahmoudi Nasab, Tim Bakker

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Introduction: Mycobacterium tuberculosis (MTB) is the most intelligent bacterium that existed in the world to our best knowledge. This bacterium can cause tuberculosis (TB) which is responsible for its spread speed and murder of millions of people around the world. MTB has the practical function to escape from anti-tuberculosis drugs (AT), for this purpose, it handles some mutations in the main genes and creates new patterns for inhibited genes. Method and materials: Researchers have their best tries to safely isolate MTB from the sputum specimens of 35 patients in some hospitals in the Tehran province and detect MTB by culture on Löwenstein-Jensen (LJ) medium and microscopic examination. DNA was extracted from the established bacterial colony by enzymatic extraction method. It was amplified by the polymerase chain reaction (PCR) method, reverse hybridization, and evaluation for detection of resistance genes; generally, researchers apply GenoType MTBDRplus assay. Results: Investigations of results declare us that 21 of the isolated specimens (about 60%) have mutation in rpoB gene, which resisted to rifampicin (most prevalence), and 8 of them (about 22.8%) have mutation in katG or inhA genes which resisted to isoniazid. Also, 4 of them (about 11.4%) don't have any mutation, and 2 of them (about 5.7%) have mutation in every three genes, which makes them resistant to the two drugs mentioned above. Conclusion: Rifampicin and isoniazid are two essential AT that using in the first line of treatment. Resistance in rpoB, and katG, and inhA genes related to mentioned drugs lead to ineffective treatment.

Keywords: mycobacterium tuberculosis, tuberculosis, drug resistance, isoniazid, rifampicin

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Authors: Yahya Toyin Muritala, Nonglaksana Kama, Ahmad Yani

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The aim of the paper is to investigate various linguistic techniques in enhancing and facilitating the acquisition of the practical knowledge of Arabic grammatical structuring among non-Arab learners of the standard classical Arabic language in non-Arabic speaking academic settings in the course of the current growth of the internationalism and cultural integration in some higher institutions. As the nature of the project requires standard investigations into the unique principal features of Arabic structurings and implications, the findings of the research work suggest some principles to follow in solving the problems faced by learners while acquiring grammatical aspects of Arabic language. The work also concentrates on the the structural features of the language in terms of inflection/parsing, structural arrangement order, functional particles, morphological formation and conformity etc. Therefore, grammatical aspect of Arabic which has gone through major stages in its early evolution of the classical stages up to the era of stagnation, development and modern stage of revitalization is a main subject matter of the paper as it is globally connected with communication and religion of Islam practiced by millions of Arabs and non-Arabs nowadays. The conclusion of the work shows new findings, through the descriptive and analytical methods, in terms of teaching language for the purpose of effective global communication with focus on methods of second language acquisitions by application.

Keywords: language structure, Arabic grammar, classical Arabic, intercultural communication, non-Arabic speaking environment and prospects

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Authors: Lina Yang, Mao Wen, Jianhong Chen, Kan Zhang

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Molybdenum disulfide (MoS₂) represents a highly sought lubricant for reducing friction based on intrinsic layered structure, but for this reason, practical applications have been greatly restricted due to the fact that its low hardness would cause severe wear. Here, a novel TiMoN/MoSₓ composite coatings with TiMoN solid solution grains embedded into MoSₓ-based amorphous matrix has been successfully designed and synthesized, through magnetron co-sputtering technology. Desirably, in virtue of such special microstructure, superhardness and excellent toughness can be well achieved, along with an ultra-low wear rate at ~2×10⁻¹¹ mm³/Nm in the air environment, simultaneously, low friction at ~0.1 is maintained. It should be noted that this wear level is almost two orders of magnitude lower than that of pure TiN coating, and is, as we know, the lowest wear rate in dry sliding. Investigations of tribofilm reveal that it is amorphous MoS₂ in nature, and its formation arises directly from the MoSₓ amorphous matrix. Which contributes to effective lubrication behavior, coupled with excellent mechanical performances of such composite coating, exceptionally low wear can be guaranteed. The findings in this work suggest that the special composite structure makes it possible for the synthesis of super-hard and super-durable lubricative coating, offering guidance to synthesize ultrahigh performance protective coating for industrial application.

Keywords: hardness, MoS₂-containing composite coatings, toughness, tribological properties

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Authors: Quang Dung Le, Kentaro Tanaka, Viet Dung Luu, Kotaro Shirai

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Mercury pollutant is great concerns in globe due to its toxicity and biomagnification through the food web. Recently increasing approaches of stable isotope analyses which have applied in food-web structure are enabled to elucidate more insight trophic transfer of pollutants in ecosystems. In this study, the integration of total mercury (Hg) and stable isotopic analyses (δ13C and δ15N) were measured from basal food sources to invertebrates and fishes in order to determine Hg transfer in Setiu lagoon food webs. The average Hg concentrations showed the increasing trend from low to high trophic levels. The result also indicated that potential Hg exposure from inside mangrove could be higher than that from the tidal flat of mangrove creek. Fish Hg concentrations are highly variable, and many factors driving this variability need further examinations. A positive correlation found between Hg concentrations and δ15N values (the trophic magnification factor was 3.02), suggesting Hg biomagnification through the lagoon food web. Almost all Hg concentrations in fishes and mud crabs did not present a risk for human consumption, however, the Hg concentrations of Caranx ignobilis exceed the permitted level could raise a concern of the potential risk for the marine system. Further investigations should be done to elucidate whether trophic relay relates to high Hg concentrations of some fish species in coastal systems.

Keywords: mercury, transfer, stable isotopes, health risk, mangrove, food web

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Authors: Manveen Singh

Abstract:

Since the very advent of law enforcement, eyewitness testimony has played a pivotal role in identifying, arresting and convicting suspects. Reliant heavily on the accuracy of human memory, nothing seems to carry more weight with the judiciary than the testimony of an actual witness. The acceptance of eyewitness testimony as a substantive piece of evidence lies embedded in the assumption that the human mind is adept at recording and storing events. Research though, has proven otherwise. Having carried out extensive study in the field of eyewitness testimony for the past 40 years, psychologists have concluded that human memory is fragile and needs to be treated carefully. The question that arises then, is how reliable is eyewitness testimony? The credibility of eyewitness testimony, simply put, depends on several factors leaving it reliable at times while not so much at others. This is further substantiated by the fact that as per scientific research, over 75 percent of all eyewitness testimonies may stand in error; quite a few of these cases resulting in life sentences. Although the advancement of scientific techniques, especially DNA testing, helped overturn many of these eyewitness testimony-based convictions, yet eyewitness identifications continue to form the backbone of most police investigations and courtroom decisions till date. What then is the solution to this long standing concern regarding the accuracy of eyewitness accounts? The present paper shall analyze the linkage between human memory and eyewitness identification as well as look at the various factors governing the credibility of eyewitness testimonies. Furthermore, it shall elaborate upon some best practices developed over the years to help reduce mistaken identifications. Thus, in the process, trace out the changing landscape of eyewitness testimony amidst the evolution of DNA and trace evidence.

Keywords: DNA, eyewitness, identification, testimony, evidence

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Authors: Seon Soon Choi

Abstract:

The principal purpose of this paper is to find the influence of maximum fatigue load on the probabilistic aspect of fatigue crack propagation life at a specified grown crack in magnesium alloys. The experiments of fatigue crack propagation are carried out in laboratory air under different conditions of the maximum fatigue loads to obtain the fatigue crack propagation data for the statistical analysis. In order to analyze the probabilistic aspect of fatigue crack propagation life, the goodness-of fit test for probability distribution of the fatigue crack propagation life at a specified grown crack is implemented through Anderson-Darling test. The good probability distribution of the fatigue crack propagation life is also verified under the conditions of the maximum fatigue loads.

Keywords: fatigue crack propagation life, magnesium alloys, maximum fatigue load, probability

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Authors: A. A. El Maghrbi

Abstract:

The control of vectors like mosquitoes based on the application of chemical insecticides but due to its adverse effect on the environment, and development of resistance by most of species of mosquitoes including vectors of important diseases. Ethanol and acetone extracts of nine species of plants (Allium tuberosum, Apium leptophylum, Carica papaya, Cymbopogon citratus, Euphorbia cotinofolia, Melia azedarach, Ocimum canum, Ricinus common, and Tagetes erecta) were tested in respect of their influence on the eggs and larvae of Culex quinquifasciatus in concentration 100, 10 and 1 mg/L. In relation to the survival of larvae, ethanol extract of O. canum and acetone extract of A.tuberosum in 100 mg/L have larvicide activity against L4 of Cx. quinquifasciatus. For hatching of eggs, ethanol and acetone extract of A.tuberosum (100 and 10 mg/L) and acetone extract of C.citratus (100 mg/L) produced reduction in the number of eggs hatched of Cx. quinquifasciatus. Our results indicate that each extract of the plant have potential to control mosquito population and suggest that further studies are needed in this field.

Keywords: Cx. quinquefasciatus, plant extract, ethanol, acetone, larvae, eggs

Procedia PDF Downloads 365

Authors: Kusno Kamil, Andi Asni, Sungkono

Abstract:

According to a report of the World Food and Agriculture Agency (FAO): the post-harvest fish losses in Indonesia reaches 30 percent from 170 trillion rupiahs of marine fisheries reserves, then the potential loss reaches 51 trillion rupiahs (end of 2016 data). This condition is caused by traditionally vulnerable fish catches damaged due to disruption of the cold chain of preservation. The physical and chemical changes in fish flesh increase rapidly, especially if exposed to the scorching heat in the middle of the sea, exacerbated by the low awareness of catch hygiene; many unclean catches which contain blood are often treated without special attention and mixed with freshly caught fish, thereby increasing the potential for faster fish spoilage. This background encourages research on traditional fisherman catch preservation methods that aim to find the best and most affordable methods and/or combinations of fish preservation methods so that they can help fishermen increase their fishing duration without worrying that their catch will be damaged, thereby reducing their economic value when returning to the beach to sell their catches. This goal is expected to be achieved through experimental methods of treatment of fresh fish catches in containers with the addition of anti-bacterial copper, liquid smoke solution, and the use of vacuum containers. The other three treatments combined the three previous treatment variables with an electrically powered cooler (temperature 0~4 ᵒC). As a control specimen, the untreated fresh fish (placed in the open air and in the refrigerator) were also prepared for comparison for 1, 3, and 6 days. To test the level of freshness of fish for each treatment, physical observations were used, which were complemented by tests for bacterial content in a trusted laboratory. The content of copper (Cu) in fish meat (which is suspected of having a negative impact on consumers) was also part of the examination on the 6th day of experimentation. The results of physical observations on the test specimens (organoleptic method) showed that preservation assisted by the use of coolers was still better for all treatment variables. The specimens, without cooling, sequentially showed that the best preservation effectiveness was the addition of copper plates, the use of vacuum containers, and then liquid smoke immersion. Especially for liquid smoke, soaking for 6 days of preservation makes the fish meat soft and easy to crumble, even though it doesn't have a bad odor. The visual observation was then complemented by the results of testing the amount of growth (or retardation) of putrefactive bacteria in each treatment of test specimens within similar observation periods. Laboratory measurements report that the minimum amount of putrefactive bacteria achieved by preservation treatment combining cooler with liquid smoke (sample A+), then cooler only (D+), copper layer inside cooler (B+), vacuum container inside cooler (C+), respectively. Other treatments in open air produced a hundred times more putrefactive bacteria. In addition, treatment of the copper layer contaminated the preserved fresh fish more than a thousand times bigger compared to the initial amount, from 0.69 to 1241.68 µg/g.

Keywords: fish, preservation, traditional, fishermen, boat

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Authors: Adnan I. O. Zaid

Abstract:

As aluminum solidifies in columnar structure with large grain size which reduces its surface quality and mechanical strength; therefore it is normally grain refined either by titanium or titanium + boron (Ti or Ti + B). In this paper, the effect of addition of either Ti or Ti + B to commercially pure aluminum on its grain size, Vickers hardness, mechanical strength and fatigue strength and life is presented and discussed. Similarly, the effect of vanadium addition to Al grain refined by Ti or Ti+ B is presented and discussed. Two binary master alloys Al-Ti and Al-Vi were laboratory prepared from which five different micro-alloys in addition to the commercially pure aluminum namely Al-Ti, Al-Ti-B, Al-V, Al-Ti-V and Al-Ti-B-V were prepared for the investigation. Finally, the effect of their addition on the fatigue cracks initiation and propagation, using scanning electron microscope, SEM, is also presented and discussed. Photomirographs and photoscans are included in the paper.

Keywords: aluminum, fatigue, grain refinement, titanium, titanium+boron, vanadium

Procedia PDF Downloads 486