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Background Traditional teaching methods via faculty lectures and text-based materials lack interactivity. Hence, this research aimed to compare the effectiveness of story-based audiovisual mnemonics and the conventional text-reading method on medical students’ memory consolidation. Methods A single-center, systematically randomly sampled, single-blinded, controlled study was conducted among 80 first-year medical students. The students were randomly assigned to the text-reading (control) or story-based audiovisual mnemonics (intervention) group. After completing the learning session, the participants immediately took a test that consisted of ten multiple-choice questions, each of which had one correct single-response answer, and an oral recall test that consisted of ten keywords based on the given topics. The test was repeated at 1 week, 2 weeks, and 4 weeks post intervention. Descriptive and inferential statistics were utilized to assess the participants’ responses. The mean score difference between the audiovisual mnemonics and control groups was determined by using a two-tailed unpaired t-test. Results The participants in the intervention group had statistically significant higher marks in the multiple-choice test as compared to the participants in the control group. The intervention group also spent a statistically significant shorter time to recall keywords in the oral recall test in comparison to the control group. Conclusion The story-based audiovisual mnemonics method is more effective than the conventional text-reading method in promoting memory retention among medical students.

Background/Aims: Proximal colorectal cancers (CRCs) account for up to half of CRCs. Sessile serrated lesions (SSLs) are precursors to CRC. Proximal location and presence of dysplasia in SSLs predict higher risks of progression to cancer. The prevalence of dysplasia in proximal SSLs (pSSLs) and clinical characteristics of dysplastic pSSLs are not well studied.Methods: Endoscopically resected colonic polyps at our center between January 2016 and December 2017 were screened for pSSLs. Data of patients with at least one pSSL were retrieved and clinicopathological features of pSSLs were analysed. pSSLs with and without dysplasia were compared for associations.Results: Ninety pSSLs were identified, 45 of which had dysplasia giving a prevalence of 50.0%. Older age (65.9 years vs. 60.1 years, p=0.034) was associated with the presence of dysplasia. Twelve pSSLs were 10 mm or larger. After adjusting for age, pSSLs ≥10 mm had an adjusted odds ratio of 5.98 (95% confidence interval, 1.21–29.6) of having dysplasia compared with smaller pSSLs.Conclusions: In our cohort of pSSLs, the prevalence of dysplasia is high at 50.0% and is associated with lesion size ≥10 mm. Endoscopic resection for all proximal serrated lesions should be en-bloc to facilitate accurate histopathological examination for dysplasia as its presence warrants shorter surveillance intervals.

IKEA is an internationally well-known largest furniture retailer. The purpose of this study is to study key determinants of IKEA's success. To reach the purpose of this research, we focused on the international strategy IKEA used to approach their customers and IKEA’s SWOT analysis. Besides, we also focus on how IKEA store layout influences consumer behavior. The primary data collection method was interviews conducted with IKEA customers by Google forms. This study found that IKEA’s unique management planning and marketing strategy attract customers to revisit the retail store.

Black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) are components of fine particulate matter associated with adverse health outcomes. However, limited work has examined the effects of PM constituents on mortality risk. Our multiple regression analysis evaluated the association of estimated neighborhood-level average fine particulate matter (PM2.5), BC, and PAH concentrations for 2013 obtained from local-scale land use regression models with 2007–2011 census tract-level age-adjusted non-accidental, cardiovascular, pulmonary, cancer, and other mortality rates in Allegheny County, PA. Models were further adjusted for census tract-level race, education, and health insurance status. In our adjusted models, estimated pollutant concentrations were not consistently associated with mortality. Only one model’s effect estimate did not include the null value, although the relationship was opposite of our original hypothesis. An interquartile range (0.25 μg/m3) increase in BC concentration was associated with a 5.9% (95% CI − 11.07, − 0.36%) decrease in log-transformed cancer mortality. However, in all mortality categories, education and health insurance covariates had a robust association with outcomes. We did not find a consistent relationship between pollutant exposures and age-adjusted mortality rates in Allegheny County, PA. However, having health insurance and having greater than a high school diploma were associated with lower mortality risk.

Snow removal is a critical security issue in airports, where heat-pipe technology can be an environmentally friendly and efficient alternative to traditional approaches for snow removal. This study investigated the long-term thermal regime of airfield-runways equipped with a heat-pipe system, using data collected over several recent years from two full-scale snow-melting systems, one located in Beijing, and the other in Harbin, China. The findings showed that the heat-pipe system automatically increases the airfield-runway surface temperatures by up to 17 °C utilizing geothermal energy in winter for preventing icing. Surface temperature levels up to 0 °C were observed to increase by over 25% when a shallow pipe embedded depth and a longer pipe evaporation section were selected. However, the surface temperature was less affected by the diameter of the heat-pipe. Field experiments indicated that, the heat-pipe technology threshold value for the airfield-runway snow-melting performance was an ambient air temperature exceeding −10 °C. Using the heat-pipe technology, the snow-melting rate on an airfield-runway was about 3–8 mm/h within the working range, and there was therefore a decrease in the snow-cover durations. Particularly, the heat-pipe airfield-runway was always free of snow when the average ambient air temperature exceeded −4 °C. The statistical results illustrated that the heat-pipe airfield-runway snow-melting system is applicable in more than 78% of the cities in China, indicating that this technology is feasible and practical in China and can be applied in other countries.

In order to take full advantage of historical data and improve the accuracy of temperature prediction, This paper combines LSTM with the Attention mechanism and proposes the LSTM-Attenion temperature prediction model.. This model is compared with the traditional LSTM model without attention mechanism. Experimental results show that the attention-based LSTM model is better than the traditional LSTM model without attention mechanism under the RMSE and MAE evaluation indicators. This model has better predictive ability in temperature prediction.

Computer vision has gained tremendous attention recently due to what visual data can provide in terms of meaningful information and predictions. Videos, not like other types of data, can carry lots of information about the captured scene. Information such as objects detection, face recognition and action classification can be beneficial to monitoring systems such as traffic monitoring and security systems. Activities recognition, in particular, is a quite significant part of visual data analysis and can provide pragmatic predictions on people’s behaviour. The absence of a well-labelled video dataset makes it more challenging to develop machine learning algorithms for irregular actions recognition. These prediction models can ease the process of monitoring buildings, roads and other common areas monitored by CCTV systems. This paper proposes a method to utilise deep learning in classifying people’s behavior by identifying normal behaviours and classifying any unusual activities and provide a well-trimmed and labelled dataset for abnormal behaviors in CCTV videos.

Medication non-adherence is one of the most significant concerns in managing chronic diseases which has inevitable consequences. While various technologies and research have been developed and carried out to monitor medical adherence for patients, their approaches lack in terms of the assurance of medicine consumption and the cost effectiveness of their solutions. This paper provides a cloud-based medical adherence system that can track patients’ medicine intake based on the physical effects of the medicine on their bodies by tracking their vital signs. A machine learning model is trained to classify the patient health status and this data is used to determine whether their bodies are responding to the medicine, which is used to alert doctors to enable home hospitalization. The use of this system is proposed to serve as a secondary decision support provider to compliment and ease the decision-making process done by doctors.

In the beam control system, the correction of optical axis is an essential process of the optical system. Adjusting the installation angle of the relay mirror is an effective way to change the optical axis direction. However, due to the forced deviation of the installation angle from the theoretical design value, the supporting structure will produce greater stress, which will affect the surface accuracy of the mirror. Therefore, we present an optimization method that can reduce the sensitivity of mirror surface. First, the surface sensitivity is introduced to measure the surface accuracy under the forced deflection angle. Second, the external response function of surface sensitivity is realized by combining dynamic link library and MATLAB. At last, the topological structure is optimized with the sum of the sensitivity weights of two cases as the objective function and the dynamic resonance frequency as the constraint. The optimized structure shows that the surface sensitivity around the x axis decreases from 2.58 nm / ± 1 ″ to 0.32 nm / ± 1 ″ , and the surface sensitivity around the y axis decreases from 3.75 nm / ± 1 ″ to 0.09 nm / ± 1 ″ .

Electrothermal performance of Resistive Random Access Memory (RRAM) composed of five different resistive switching oxides is studied numerically in this paper. Finite element method-based parallel computing simulator is employed to conduct the electrothermal simulation of both RRAM cell and array. Simulation results indicate that NiO and ZrO x RRAMs generate higher heat than HfO x , TiO x and ZnO x RRAMs, as their electric conductivity are higher in the same voltage. During the reset, ZnO x RRAM requires lower voltage to be transferred into high-resistance state due to its higher oxygen vacancy drift rate. The heat crosstalk problem in RRAM array is also investigated, which can decrease reliability during the reset of RRAM. Inactive cells can be transferred into high-resistance state unintentionally with stored information lost. In the same voltage, both HfO x and TiO x RRAMs are less affected by heat crosstalk due to their lower oxygen vacancy drift rate.

Heat pipe technology has been demonstrated to melt ice and snow in airfield rigid pavement, and field observations indicate that it achieves satisfactory effects. However, the impacts of heat pipes on pavement responses are unclear. This paper compared the responses of traditional versus snow-melting airfield rigid pavement under aircraft loads, temperature loads, and their coupling effects by the means of field tests and a three-dimensional finite element (3D FE) model. The effects of types of interface contact on pavement responses were also modeled and discussed. The results show that introduction of heat pipe does not change the mechanical-induced responses of pavement. However, it significantly decreases the maximum thermal stresses by reducing the internal temperature gradient of concrete layer. Besides, the maximum principle stress induced by coupling effects of aircraft loads and extremely thermal loads decreases significantly when heat pipe is embedded. Such coupling stress is independent on the type of interface contact conditions. Overall, heat pipe can potentially postpone pavement deterioration and damage extents, such as thermal cracking and fatigue cracking.

High spatial resolution is of great significance for the γ -ray imaging technique, whose performance is mainly limited by the spatial resolution of position sensitive detectors (PSDs). In this work, the compressive coded aperture is introduced in γ -ray imaging as the basic pattern, and enlarged with the “mosaic” method to increase the Fully Coded Field of View (FCFV) of the PSDs. In order to demonstrate the performance of the compressive coded aperture, Monte-Carlo simulations of the encoding process have been performed for the mosaiced compressive coded aperture as well as the Modified Uniformly Redundant Arrays (MURA) coded aperture. The encoded image of the compressive coded aperture is reconstructed using the sparse reconstruction algorithm based on interior point method, with Discrete Cosine Transform (DCT) basis, Haar wavelet basis and Discrete Fourier Transform (DFT) basis respectively, and the encoded image of the MURA coded aperture is reconstructed respectively with the sparse method and the Maximum-Likelihood, Expectation-Maximization (MLEM) algorithm. In comparison with the MURA coded aperture reconstructed with the MLEM method, higher resolution images can be obtained from lower resolution detectors with both compressive coded aperture and MURA coded aperture using the sparse method. However, with the sparse method, the compressive coded aperture leads to higher quality images than the MURA coded aperture does.

In this paper, a new virtual synchronous generator (VSG) strategy based on the V2-P droop control strategy is proposed for the voltage source converter based multi-terminal high voltage direct current (VSC-MTDC) system. The VSG strategy enables the inverter stations to damp the power oscillation and provide frequency support for the AC system. Virtual inertia coefficient is obtained to couple the DC voltage and the angular frequency. To provide the oscillation damping and frequency support, the inverter stations could adjust the output power by the adjustment of the DC reference voltage. Due to the characteristic of the V2-P droop method, there is no requirement for the communication between inverter stations. The Monte Carlo method is used to test the probabilistic small signal stability of the VSG strategy. The performance of the proposed controller is demonstrated by a hybrid AC/DC system which is modeled in DIgSILENT/PowerFactory.

In the 21st century, technology utilization is required in most of the workplaces because it helps to accelerate the pace of globalization and increase the organization's competitiveness. Utilizing ICT in education can be considered as an effective enabler to create access, store, transmit, and manipulate different information in audio and visual form, due to its capabilities in providing proactive teaching and learning environment. ICT utilization in education can be used for various purposes such as active teaching and learning, students' engagement, and administrative tasks. Administrative support plays a significant role in the effective and efficient utilization of technology in educational institutions. This piece of work presents a comprehensive review of the relevant literature regarding ICT utilization and Administrative supports in education settings. In addition, this chapter elaborates on the relevant theories to technology use and administrative supports and their key dimensions.

Coal is an important resource that has supported China&rsquo, s economic development. This situation is expected to continue in the immediate future. However, coal mining has also led to serious environmental disasters in some mining areas. Henan Province is one of the 14 large-scale coal bases that are planned by the Chinese state. It is located in the transitional zone between the second and third terrain ladders of China and spans two tectonic units. The geological features and ecological environmental characteristics display wide spatial variations throughout this district, which is an ecologically fragile region of stepped transition type. However, large-scale, extremely intense coal mining activities will inevitably lead to further deterioration of the already fragile ecological and geological (eco-geological) environment, which makes recovery increasingly difficult. Based on the condition of the eco-geological environment and the coal mining industry in the Henan mining area, the mechanisms by which mining-induced damage can occur were analyzed. The characteristics and status of the destruction of ground structures, land resources, water resources, the atmospheric environment, and natural ecology are discussed in this paper. Appropriate mitigation measures are proposed based on the findings. This mainly includes: management practices to prevent and mitigate damage throughout all stages of mining, adoption of mining techniques that will control damage at the source, and, the adoption of appropriate post-mining recovery technologies. The analysis of mining-induced eco-geological environmental damage and mitigation measures is of importance for the prevention of eco-geological disasters, and the promotion of efficient and environmentally sustainable exploitation of coal resources.

Based on metamaterial theory, a terahertz metamaterials with analog of electromagnetically induced transparency (EIT) effect is designed. The cell unit are consisted of three metal wires and polyimide substrates. Through the radiation of the terahertz wave, the bright-dark mode is excited directly and indirectly to form the EIT resonance, and the phase interference is formed through the superposition of the resonant spectrum between the elements to make the metamaterial transparent to the incident terahertz wave. The formation of transparent window has great value in the application of loss detection. In this paper, the influence of the loss of the measured material on the transmission peak is studied based on the change of the peak of transmission peak. The result shows that there is a close nonlinear relationship between the loss tangent angle of the measured material and the penetration rate of the metamaterial, which provided ideas and foundations in the measurement of the loss detection.

Walking has significantly contributed to a lower carbon emission of a country. With the aspiration of a lesser carbon footprint zone, the initiatives of understanding the current pedestrian system are crucial. Although walking improves green mobility, it is still known as the least preferred mode. Thus, this study aims to improve pedestrian walkways and promote a higher level of usage of pedestrian walkways by analyzing the critical factors contributing to the lower carbon footprint among the urban dwellers. The results will help to improve a lower carbon footprint practice in the metropolitan area.Keywords: Pedestrian,Friendly,Low Carbon,SatisfactioneISSN: 2398-4287 © 2020. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.DOI: https://doi.org/10.21834/e-bpj.v5i13.1982

The rapid rise and widespread of ‘Fake News’ has severe implications in the society today. Much efforts have been directed towards the development of methods to verify news reliability on the Internet in recent years. In this paper, an automated news reliability evaluation system was proposed. The system utilizes term several Natural Language Processing (NLP) techniques such as Term Frequency-Inverse Document Frequency (TF-IDF), Phrase Detection and Cosine Similarity in tandem with Latent Semantic Analysis (LSA). A collection of 9203 labelled articles from both reliable and unreliable sources were collected. This dataset was then applied random test-train split to create the training dataset and testing dataset. The final results obtained shows 81.87% for precision and 86.95% for recall with the accuracy being 73.33%.

Network downtime is one of the most widely shared phenomenon within the telecommunications infrastructure. In particular, faults from network equipment have received the most attention. Proactive network monitoring system is presented in this paper to address the earliest symptoms of malfunctioning network equipment. Research focus has been placed on learning the network's behavior as well as on detecting deviations from the MSAN (Multi-Service Access Node) norm at the access layer. Additionally, this paper aims to provide an overview in handling the MSAN equipment, warnings, and implementation of Naive Bayes classifier. Results demonstrated the throughput performance associated with the equipment activities log.

Evacuation model is an important tool in formulating performance-based building design. It is a tool aims at helping designers assess the robustness of their design against factors such as human behaviour in fire. Currently, performance-based code for fire safety design has been the hot trend all over the world. Nevertheless, even though Malaysia is applying prescriptive-based code, performance-based approach for special buildings and mega projects are allowed. This shows that it is just a matter of time before performance-based code be fully adopted in place of prescriptive-based code in Malaysia. This paper aims to highlight how evacuation modelling may help designers assess the performance of their design. In this paper, an example of evacuation scenario was modelled and simulated using an agent-based fire evacuation model – FDS+Evac. The output of the simulation provide graphical representation such as the fire curve, the evacuation time, and the time to untenable condition that can be used to analyse the life safety objective based on concepts of ASET and RSET. The FED values of all occupants throughout the evacuation process are less than tenability criteria (0.3 FED). Therefore, it is concluded that all occupants have evacuated safely in the event of fire.

Compaction quality control (QC) of asphalt pavement is an important operation, which still lacks of real-time and convenient methods to achieve the controlling goals. Based on the principle of fibre Bragg grating (FBG) sensing technology and hypothesis of relationship between material stable performance and deformation property, a framework for QC of asphalt pavement compaction using FBG sensing technology was provided. Simulation laboratory experiments which included compaction and loading test of a composite rutting plate embedded FBG sensor were carried out. According to monitoring indicator found in laboratory tests, the QC method was practiced in an engineering project. Results indicate that FBG sensing technology can effectively catch rolling response information. When the value of indicator S DI obtained from the response information approaches to zero for the second time in succession, rolling pass number can ensure asphalt mixture meet compactness requirement. Results of laboratory test and data from engineering application are in good conformity. The effective compaction control distance is ±90 m from measuring point. FBG sensors embedded in asphalt pavement not only can identify the weak compacting areas on the basis of different FBG sensor response values, but also can be used for long-term monitoring of pavement structural behaviour.

Computer vision technology may improve the accuracy and robustness of estrus detection in dairy cows. In this study, we proposed a method for detecting mounting behavior in dairy cattle using the geometric and optical flow characteristics of identified image regions in videos taken on dairy farms. Videos captured on a farm often have a complex background, which can interfere with target detection. In this study, we used masking technology to remove the unrelated background, converted the RGB color space to HSV color space, and adjusted the summation coefficients of the HSV channels to improve the contrast between the cows and background images. Subsequently, the proposed Background Subtraction with Color and Texture Features (BSCTF) algorithm was used to detect cow regions. Then, to perform inter-frame differential processing on detection regions, the geometric and optical flow characteristics of the regions were extracted, and seven optimized features were used to construct regional feature vectors. Finally, a support vector machine (SVM) classifier was trained to classify the detected regions into mounting regions and non-mounting regions, which allowed the identification of mounting behavior. We obtained accuracy and omission rates of this detection method of 98.3% and 6.4%, respectively. The average recognition accuracy and false positive rates of the SVM classifier were 90.9% and 4.2%, respectively. These results demonstrate that the proposed method is effective for detecting the mounting behavior of dairy cows and is convenient for further judging whether cows are in estrus.

The structure parameters of fast-steering mirror (FSM) might change with time goes by. In order to reduce the impact of this change on the output performance of FSM system, an incomplete derivative fuzzy PID control system is proposed. This control system can effectively improve the time domain quality of FSM system by optimizing the PID control parameters online. First, the dynamic model of FSM is established. Second, the initial parameters of the incomplete derivative PID control system are designed according to the frequency domain quality of the closed-loop system. Then, the rules and related factors of the fuzzy controller are designed on the basis of the initial parameters. Finally, simulation experiments are carried out. The results show that the incomplete derivative PID control system has shorter adjustment time, less overshoot and lower dependence on the parameters of FSM when compared with the fixed parameters PID control system.

Adaptive optics is an important technology for improving beam quality in solid-state slab lasers. However, there are uncorrectable aberrations in partial areas of the beam. In the criterion of the conventional least-squares reconstruction method, it makes the zones with small aberrations nonsensitive and hinders this zone from being further corrected. In this paper, a weighted least-squares reconstruction method is proposed to improve the relative sensitivity of zones with small aberrations and to further improve beam quality. Relatively small weights are applied to the zones with large residual aberrations. Comparisons of results show that peak intensity in the far field improved from 1242 analog digital units (ADU) to 2248 ADU, and beam quality β improved from 2.5 to 2.0. This indicates the weighted least-squares method has better performance than the least-squares reconstruction method when there are large zonal uncorrectable aberrations in the slab laser system.

Because the thermal stress restrained specimen test (TSRST) is recommended by the Strategic Highway Research Program (SHRP) as a test method to evaluate low-temperature cracking resistance of asphalt mixtures, many studies have been carried out to investigate the performance of asphalt mixture with this test using fracture temperature as the indicator. However, few of them focus on discussing its reliability. In this paper, six kinds of asphalts mixtures are evaluated by TSRST, and it is found that the evaluation results obtained by the four indices are contradictory. It is also inferred from the results of each index coefficient of variation that fracture temperature and transition temperature are more stable when they are used to evaluate low-temperature performance of asphalt mixtures. Through the application of principal-component analysis (PCA) and the Boston Consulting Group’s matrix on the TSRST results, it is demonstrated that fracture temperature used as the indicator of low-temperature p...

In order to approve the direction property of multi-element linear ultrasonic transducer array, the multi-element phase-controlled technique was adopted. Here we have explored the detected direction influence from dominant frequency, number of multi-element transducer and space between transducer on direction of multi-element linearultrasonic transducer array. These results show that large sub-array has good direction property when the main frequency of detector is low. However it is contrary for high frequency of ultrasonic detector. This will be significative in photoacoustic signal detection and image reconstruction.

This study investigates the benefits of modifying asphalt and stone-matrix-asphalt (SMA) mixtures in flexible pavement. 70/100-penetration-grade asphalt cement and 5% styrene-butadiene-styrene (SBS...

Ultrasound-modulated optical imaging technology is a new type of biological tissue optical detection technology, and sensitive to the change of scattering coefficient and absorption coefficient of biological tissue. This technology is a non-ionizing and non-invasive pathological detection method, which has great potential application in early detection of cancer. However, ultrasound-modulated optical imaging technology is insufficient in signal-to-noise ratio (SNR) and imaging contrast. Frequency-shifted laser feedback technology with microchip laser is a new type of highly sensitive interference technology, whose gain coefficient for weak optical signal can reach 106. This technology can greatly improve the SNR of imaging. Combined with the high sensitive laser feedback technology, the ultrasound-modulated laser feedback technology is proposed. The SNR of this technology is better than that of the traditional ultrasound-modulated optical imaging technology. The increase in SNR can achieve greater depth of detection in biological tissue imaging, but there is no significant improvement in imaging contrast. In order to improve the contrast of biological tissue imaging and achieve high resolution imaging of thick biological tissue, we use ultrasound microbubble contrast agent in ultrasound-modulated laser feedback imaging technology. We establish a Monte Carlo photon transport model with microbubbles in order to study the mechanism of contrast enhancement in ultrasound-modulated laser feedback imaging with microbubbles. Finally, we establish an experimental system to verify the correctness of the simulation results. Experimental and simulation results show that in the transparent solution, the ultrasonic microbubble contrast agent can enhance the ultrasound-modulated laser feedback signal and generate harmonic modulation, which can improve the imaging contrast by detecting the enhancement of the fundamental and harmonic signals of the feedback. In the scattering medium, the ultrasonic microbubble contrast agent can significantly attenuate the ultrasound modulated laser feedback signal, and the imaging contrast can be improved by detecting the attenuation of the fundamental and harmonic signal.

This paper investigates the viability of using starch (ST) as a new modifier for asphalt paving materials. Different ratios of ST (2.5, 5.0, and 7.5% by weight of asphalt) were blended with 70/100 paving grade asphalt. Unmodified and modified asphalt binders were subjected to physicochemical, alkali, acid and fuel resistance tests. The performance tests including, Marshall stability, Marshall Quotient (MQ), tensile strength, tensile strength ratio, flexural strength, rutting resistance and resilient modulus (MR) were carried out on unmodified and modified stone matrix asphalt (SMA) mixtures. The analyses of test results show that the performance of ST-modified asphalt mixtures are better than conventional and styrene–butadiene–styrene (SBS)-modified mixtures. The rutting potential, moisture susceptibility and temperature susceptibility can be reduced by the inclusion of ST in the asphalt mixture. The laboratory MR values are lower than the calculated ones using the empirical equations. The results also revealed that this modifier can be used as anti-stripping agent. It also shows resistance to fuels and most common chemicals. A ST content of 5% by weight of asphalt is recommended for the improvement of the performance of asphalt concrete mixtures similar to that investigated in this study.

In the asphalt mixtures, although asphalt is predominantly considered the binder holding the aggregates together, the actual product used to connect aggregate particles is the asphalt-mineral filler mastic which consists of the asphalt and mineral filler. The characterization of asphalt-mineral filler mastic is essential to improve the understanding of the response and performance of asphalt concrete pavements. It is also important to understand the high- and low-temperature properties of asphalt-mineral filler mastic. In this paper, the parameters of the viscous component of the repeat creep stiffness Gv were evaluated using a dynamic shear rheometer; and the creep stiffness modulus S was determined using a bending beam rheometer. The effects of filler/asphalt ratios F/A (on a weight basis) on the high-temperature and low-temperature properties of different asphalt-mineral filler mastics were studied. The results showed that the rheological behavior of asphalt-mineral filler mastics are nonlinear, and fo...

Styrene-butadiene-styrene (SBS) and starch (ST) have been used by many to modify asphalt cement and to improve the properties of asphalt concrete. In this investigation, SBS and ST were used to modify asphalt cement. The basic properties of modified asphalt binders and stone mastic asphalt concrete (SMAC) containing such asphalt binders were studied and compared with those of asphalt cement. Marshall stability, Marshall Quotient, tensile strength, tensile strength ratio, rutting resistance, flexural strength, and resilient modulus were carried out on the SMAC. A mechanistic-empirical design approach was used for estimating the improvement in service life of the pavement or reduction in thickness of SMAC and base layer for the same service life due to modification the SMAC. In addition, an optimization table was prepared to select the type of SMAC for any field applications. The analyzes of test results show that the performance of SBS-modified SMAC is slightly better when compared to ST-modified SMAC. The temperature susceptibility can be reduced by the inclusion of SBS and ST in the SMAC. The results of multilayer elastic analysis presented herein indicate that the pavement consisting of SBS and ST-modified SMAC as a surface layer is beneficial in reducing the construction materials. Actual savings would depend upon the option exercised by the designer for reducing the thickness of an individual layer.

External-cavity birefringence feedback effects of the microchip Nd: YAG laser are presented. When a birefringence element is placed in the external feedback cavity of the laser, two orthogonally polarized laser beams with a phase difference are output. The phase difference is twice as large as the phase retardation in the external cavity along the two orthogonal directions. The variable extra-cavity birefringence, caused by rotation of the external-cavity birefringence element, results in tunable phase difference between the two orthogonally polarized beams. This means that the roll angle information has been translated to phase difference of two output laser beams. A theoretical analysis based on the Fabry–Perot cavity equivalent model and refractive index ellipsoid is presented, which is in good agreement with the experimental results. This phenomenon has potential applications for roll angle measurement.

The present study investigates the benefits of modifying the asphalt and stone matrix asphalt (SMA) mixture in flexible pavement. Fifty/sixty penetration grade asphalt cement and four proportion of pyrolisis polypropylene (PP) were selected. Unmodified and modified asphalt binders were subjected to rheological and homogeneity tests. The performance tests including, Marshall stability, tensile strength and compressive strength were conducted on unmodified and modified SMA mixtures. The regression relationships between the performance tests were obtained. A mechanistic-empirical design approach was used for estimating the improvement in service life of the pavement or reduction in thickness of SMA and base layer for the same service life due to modification the SMA mixtures. The analyses of test results show that the performance of PP-modified asphalt mixtures are better when compared to conventional mixtures. The temperature susceptibility can be reduced by the inclusion of PP in the asphalt mixture. A PP content of 5% by weight of asphalt is recommended for the improvement of the performance of asphalt concrete mixtures similar to that investigated in this study. The results of multi-layer elastic analysis presented herein indicate that the pavement consisting of PP-modified SMA as a surface layer is beneficial in reducing the construction materials. Actual savings would depend upon the option exercised by the designer for reducing the thickness of an individual layer.

The present study investigates the potential use of pyrolysis low density polyethylene (LDPE) as a modifier for asphalt paving materials. Five different blends including conventional mix were subjected to binder testing such as rheological tests, as well as to some other tests related to the homogeneity of the system. Further, its effect on the moisture sensitivity and low temperature performance of stone matrix asphalt (SMA) mixtures was studied. Research results indicate that modified binders showed higher softening point, keeping the values of ductility at minimum range of specification of (100+ cm), and caused a reduction in percentage loss of weight due to heat and air (i.e. increase durability of original asphalt). The results indicated that the inclusion of LDPE in SMA mixtures can satisfy the performance requirement of high-temperature, low temperature and much rain zone. In addition, the horizontal tensile strain at the bottom of asphalt concrete layer (Et) and the vertical compressive strain at the top of subgrade layer (Ec) were calculated using multi-layer elastic analysis program, BISAR under 50KN set of dual tires with 106.5 mm contact radius. These responses were used for estimating the improvement in service life of the pavement or reduction in thickness of SMA and base layer for the same service life due to modification the SMA mixtures.

This paper presents the anisotropic optical feedback of a single frequency intra-cavity He–Ne laser. A novel phenomenon was discovered that the laser output an elliptical polarized frequency instead of the initial linear polarized one. Two intensities with a phase difference were detected, both of which were modulated in the form of cosine wave and a fringe shift corresponds to a λ/2 movement of the feedback mirror. The phase difference can be continuously modulated by the wave plate in the external cavity. Frequency stabilization was used to stabilize the laser frequency so as to enlarge the measuring range and improve the measurement precision. This anisotropic optical feedback system offers a potential displacement measurement technology with the function of subdivision of λ/2 and in-time direction judgment. The three-mirror Fabry–Perot cavity model is used to present the experimental results. Given the lack of need of lasing adjustment, this full intra-cavity laser can significantly improve the simplicity and stability of the optical feedback system.

We present a microchip laser feedback interferometer with an optical path multiplier to enhance the resolution of traditional laser feedback interferometers (LFI). The optical path multiplier has a unique device, i.e. diffusive reflector. As class B microchip lasers have extremely high sensitivity to laser feedback, the diffusive reflector can easily reflect or diffuse back the laser beam without much manual adjustment to the optical system, which ensures the system's easy-adjustment and practical feature. The optical path multiplier is a two-mirror system which enables the laser beam to reflect between the two mirrors by N times. When the target shifts a distance of Δd, the variation of the optical path will be about (AN × Δd). Thus the system's resolution is about 4N times as high as the traditional LFI. Under typical room conditions, the optical path multiplier can effectively enhance the system's resolution by more than 26 times as high as a traditional LFI system and even to the level of 0.1 nm.

The orthogonally linearly polarized dual frequency Nd:YAG lasers with two quarter wave plates in laser resonator are proposed. The intra-cavity variable birefringence, which is caused by relative rotation of these two wave plates in laser inner cavity, results in the frequency difference of the dual frequency laser also changeable. The theory model based on the Jones matrix is presented, as well as experimental results. The potential application of this phenomenon in precision roll-angle measurement is also discussed.