bluuebunny/crossref_metadata_2025 huggingface dataset:
A method for UAV monitoring road conditions in dangerous environment
Authors: Wang Xi , OuYang Chengtian , Shao Xiangling , Xu Hui
Published: February 2021

This paper analyzes the scene of UAV executing path monitoring task in dangerous environment, and puts forward a method for UAV path selection in dangerous environment. In the proposed method, the operator mode and the agent operator mode are provided, and the model checking tool prism is used to model and verify the path selection scene of UAV. In normal environment, the UAV performs the path selection under the operator mode, and counts the number of successful and failed photographing of UAV. When the UAV reaches the harsh environment area and loses contact with the operator, the UAV path in the past is analyzed through the agent operator mode, the judgment of the operator is simulated to enable the UAV to continue to carry out the path monitoring task. The UAV road condition monitoring scene in dangerous environment is analyzed and verified from different scales and different operator characteristics.
User Abnormal Viewing Behavior Detection Method Based On Canopy-FCM and Improved Isolation Forest Algorithm
Authors: Wu Yu , Liu Huiyong
Published: February 2021

In order to analyze the users’ viewing behavior more accurately, allow IPTV service providers to provide better services to users, and improve the user’s viewing experience, this paper proposes a detection method of abnormal user viewing behavior based on Canopy-FCM and improved isolation forest algorithm. First, the collected viewership data is preprocessed and stored with the user viewing behavior matrix, then the Canopy-FCM clustering algorithm is used to classify users with the same rating behavior. Then, an improved isolated forest algorithm is used to perform anomaly detection and analysis on the users classified above, and finally screen out abnormal user viewing behaviors. Finally, NMI indicators and ROC curves are used to evaluate the performance of the proposed algorithm to verify the feasibility of the proposed anomaly detection method. The results show that the method proposed in this paper has a high precision and recall rate for detecting users with abnormal ratings.
Research on the Algorithm of Locating and Cutting in License Plate Character Extraction
Authors: Yuan Bingjie , Yang Yuqing
Published: February 2021

To improve the real-time and accuracy of intelligent vehicle character recognition algorithm, this paper mainly studies a new method for license plate location and character cutting: license plate location is carried out by combining HSV color space recognition with Sobel edge detection. The outer rectangle of the outermost contour of the character is used to judge the character boundary and segment the character. First, the original picture is converted to the HSV space, then the color information of the license plate is combined with the edge information to locate the license plate roughly, and finally the specific position of the license plate is determined according to the aspect ratio of the license plate. The location of the license plate is extracted for character segmentation preprocessing. Then, by traversing, the contour which meets the aspect ratio condition is found and the corresponding circumscribed rectangle is taken. The coordinate information of the rectangle is extracted and stored as a matrix, which is the basis of character segmentation. It is proved that this method has better accuracy and reliability than the traditional methods.
Method of moments with a choice of special basic functions for fourth-order partial differential equations
Authors: Hieu L M , Hien N N , Thanh D N H , Van L T H
Published: February 2021

This paper presents an approximation method to solve the boundary value problem (BVP) for partial differential equations (PDEs) of a kind of the fourth order with the idea of discretization of a spatial variable by using the method of moments with a choice of special basic functions. A system of ordinary differential equations (ODEs) is obtained by multiplying the original equation by some auxiliary functions, followed by interpolation and integration over the spatial variable. Newton-Stirling, Hermite-Birkhoff and Hermite interpolations are flexibly applied to internal and pre-boundary nodes. In addition, boundary conditions are automatically satisfied without being approximated separately as in classical numerical methods (for example, method of grids, method of lines). Thus, the proposed schemes have a higher order of approximation. The main goal of the work is the construction of basic functions for a fourth-order differential operator and a possible increase in the order of the remainder term when passing to difference equations.
Recommendation System for Department Selection at Vocational High School (VHS) Using the Yager Model Fuzzy Multi-Attribute Decision Making (FMADM) Method
Authors: Syafitri N A , Wiharto  , Suryani E
Published: February 2021

The rapid growth of technology and knowledge requires efforts to improve human resources, one of which is improving the quality of vocational education. Vocational education is the implementation of formal education channels held in higher education one of which is the Vocational High School (VHS). VHS graduates with quality potential can increase superior human resources. The problems encountered are students who want to enter vocational schools, often have difficulty in choosing majors by their potential, mistakes in choosing majors cause students who have entered vocational schools to become graduates who are less superior. One of the solutions to this problem is to create a system that can recommend majors that are in sequence with student potential. One of the benefits if the students know the major recommendations according to student abilities, then when students carry out academic leraning will produce optimal achievement and be able to develop their abilities to the maximum and become superior vocational high school graduates. The method used in the calculation of this study is the Yager Model Fuzzy Multi-Attribute Decision Making (FMADM) method to provide the results of the major’s recommendations by student potential. The attributes used in the selection of these majors are academic value, talent value, interest value, intelligence quotient (IQ), parental support levels, achievement motivation, student’s attitude, student’s independence, and student’s health. Testing the recommendation system for the selection of VHS majors using the Yager Model FMADM method is obtained in the first scenario, the results of the recommendations at the top 10 results in an appropriate conformity value of 95.00% and not 5.00%. In the second scenario, the results of the recommendations at level 3 result in an appropriate suitability value of 82.50% and an unsuitable value of 17.50%. Based on this suitability, the FMADM Model Yager method can be implemented and produce recommendations according to student potential.
Development of highly durable retinal prosthesis using photoelectric dyes coupled to polyethylene film and quantitative in vitro evaluation of its durability
Authors: Yamashita Koichiro , Tanaka Tenu , Matsuo Toshihiko , Uchida Tetsuya
Published: February 2021

Retinal prostheses have been developed to restore vision in blind patients suffering from such diseases as retinitis pigmentosa. In our previous studies, we developed a retinal prosthesis called dye-coupled film by chemical coupling of photoelectric dyes, which absorb light and then generate electrical potential, with a polyethylene film surface. The dye-coupled film is nontoxic, and we recovered the vision of a monkey with macular degeneration. The amount of dye on the dye-coupled film, however, decreased to one-third after five months in the monkey’s eye. The photoelectric dye consists of a cation with photoresponsivity and a bromide ion (Br−). Therefore, an anion-exchange reaction could be applied to the dye-coupled film to improve its durability. In this study, the anion-exchange reaction was conducted using bis(trifluoromethanesulfonyl)imide ion (TFSI−), which has lower nucleophilicity than Br−. First, the long-term durability was examined without using animal subjects and in a short period. Subsequently, an elemental analysis was performed to confirm the exchange between Br− and TFSI−, and chemical properties, such as photoresponsivity and durability, before and after the anion exchange, were evaluated. It was quantitatively confirmed that the long-term durability of dye-coupled films can be evaluated in an in vitro environment and in a short period of one-thirtieth by utilizing a saline solution at 60 °C, compared with an in vivo environment. In addition, the durability of the dye-coupled film with TFSI− was improved to 270%–320% compared with that of the dye-coupled film with Br−.
Macrophages activated by akermanite/alginate composite hydrogel stimulate migration of bone marrow-derived mesenchymal stem cells
Authors: Zhu Yanlun , Deng Shuai , Ma Zhijie , Kong Lingzhi , Li Haiyan , Chan Hon Fai
Published: February 2021

Akermanite (Aker) has been widely used for bone regeneration through regulating osteogenesis of bone marrow-derived mesenchymal stem cells (BMSCs). Previously, we developed an injectable Aker/sodium alginate (Aker/SA) hydrogel to facilitate bone regeneration. However, the effect of this injectable hydrogel on the in vivo response, particularly the inflammatory response, has not been fully understood. Here, to elucidate the response following the implantable of Aker/SA hydrogel, we investigated the interaction among Aker/SA hydrogel, inflammatory cells and cells involved in bone regeneration (BMSCs). Specifically, we cultured macrophages (RAW 264.7 cell line) with the extract liquid of Aker/SA and assessed their phenotypic changes. Subsequently, BMSCs (2 × 105 cells per 24 well) were cultured with different conditioned media including that of Aker/SA hydrogel-activated macrophages to investigate their effect on cell migration. Finally, Aker/SA hydrogel was injected subcutaneously (1 × 106 cells ml−1) in rat to verify its effect in vivo. The in vitro results indicated that Aker/SA hydrogel activated macrophages towards M2 phenotype and stimulated macrophages to express anti-inflammatory factors. In addition, the conditioned medium collected from Aker-activated macrophages could accelerate the migration of BMSCs in 24 h. Consistent with the in vitro results, when the Aker/SA hydrogel was injected subcutaneously, more M2 macrophages could be observed than when the SA solution was injected after 7 d. Besides, when BMSCs were delivered via subcutaneous injection, more BMSCs were recruited by the Aker/SA hydrogel than the SA solution. All these results suggest that the Aker/SA hydrogel can modulate the immune environment at the implantation site and subsequently recruit BMSCs, which can be one of the mechanisms through which the Aker/SA hydrogel accelerates new bone formation.
The 300 years cropland changes reflecting climate impacts and social resilience at the Yellow River–Huangshui River Valley, China
Authors: Chen Qiong , Yang Liang Emlyn , Luo Jing , Liu Fenggui , Zhang Yili , Zhou Qiang , Guo Rong , Gu Xijing
Published: February 2021

Changes of croplands often reflect the combined impacts of both natural environment changes and social agriculture activities. Such reflections manifested more significantly in agro-pastoral transition zones, e.g. in the North and West of China. In this study, cropland changes at the Yellow River–Huangshui River Valley, as a typical agro-pastoral transition zone in northwestern China, is analyzed in terms of the changes of the total amount and spatial pattern over the past 300 years (majorly in the Qing Dynasty). The reconstructed cropland data indicated a fluctuation of cropland areas in accordance with changes of regional climate conditions, natural hazards, agriculture activities and socio-economic development. A significant decrease of cropland in the middle of the 19th century was detected, which appeared a good consistency with the frequent natural disasters in the same period and the climate cooling trend across the whole 19th century. Though in the worsening conditions, three major copping strategies maintained and developed the local socio-agriculture system: (a) land reclamation policy encouraged immigrants and military farming; (b) construction of water conservancy facilities increased agricultural productivity; (c) increasing local Tibetans learned and transformed to implementing both agriculture and pastoral productions with flexibilities depending on climate conditions. The study demonstrates that the social-agriculture system held certain resilience, which can be maintained and enhanced with appropriate political, engineering, economic, and social-cultural measures.
Unemployment of the built environment graduates
Authors: Fika M , Adeniran AA , Botha B
Published: February 2021

The challenge of unemployment of built environment graduates is recurrent and this paper aims at presenting findings on the inherent factors therein and make recommendations towards ameliorating this challenge. A quantitative method was adopted for the data collection and the data was organized, analyzed and presented with descriptive statistics. The population sample was limited to the Nelson Mandela University Built Environment Graduates. The study discovered that there were difficulties in securing employment as a result of lack of practical experience, current curriculum and the dearth of skills. The study provides information towards the resolving this challenge arising from the factors identified as causative for unemployability and identifies the need for taught and practical skill and experience to be embedded in the curriculum to stimulate the level of employability.
Household Water Stress, Adaptation and Resilience in Some Selected Peri-urban and Rural Communities of Oyo State, Nigeria
Authors: Popoola Ayobami , Magidimisha-Chipingu Hangwelani , Chipungu Lovemore , Adeleye Bamiji , Akogun Olawale , Medayese Samuel
Published: February 2021

The condition of water infrastructure in selected village communities along peri-urban and rural corridors of Oyo State can be said to be in a state of colossal infrastructural waste and communal neglect. Using a mixed approach, the study examines household water stress and adaptation. Evidence shows that peri-urban villages and rural areas in Oyo State buy water and that water facility maintenance is limited by the high cost of repairs and limited inter-community cooperation. It was also revealed that many households are vulnerable to water-borne diseases owing to a lack of a potable water source. It was revealed 50.4% of the households travel less than 30m to fetch potable water, 17.1% travel between 31 to 60m, while the remaining 32.5% travel over 100m to fetch water. The study suggests that the strategic location of the capital city and LGAs’ headquarters must be considered as this often influences water infrastructure access and availability. The strategic location of infrastructure is considered relevant in the transformation of the selected communities towards sustainability environment and improved liveability.
The need to improve current waste management practices in the area of construction waste reduction
Authors: Mbadugha L C , Ozumba Aghaegbuna O U , Shakantu Winston M W
Published: February 2021

The study will appraise the need to improve current waste management practices in the area of construction waste reduction. An integrative review of purposively sampled literature on CW construction waste reduction practice is used to arrive at propositions for an improved practice to achieve more sustainable outcomes. The study will establish the need for a paradigm shift in waste management researches in the area of construction waste reduction to target a higher degree of such philosophy at building design development stage, and not just quantity reduction. Results show that existing waste reduction practices are sub-optimally exploited, which appears as consistent waste generation. There is an opportunity for quality results when the industry aims at best the practice that will affect the process, quality, and performance during the building design process. This study will inform the construction professionals to aim at achieving more than just waste reduction at building design development.
The potential for economic impact of the KZN department of education infrastructure delivery programme
Authors: Mashigo A S , Javani B , Babatunde O K
Published: February 2021

The purpose of this study was to look at the KwaZulu-Natal (KZN) Department of Education (DoE) infrastructure delivery programme in a bid to assess its potential impact on the economic growth of KZN. A mixed research approach was used to analyse existing data obtained through document review and semi-structured cross-sectional interview design with contractors to establish the link between their actions and elements of the GDP. The triangulated empirical findings suggest that KZN’s DOE infrastructure delivery programme has a low potential to impact economic growth. The practical implications include the low impact arising from no concerted efforts to align programmes to economic fundamentals and leakages arising from inefficiencies, red tape, low capacity utilisation of resources, the poor performance of agents, consultants, contractors and low staff productivity. Recommendations were further made on institutional reforms, policy enhancement and reduction of transactions costs in the value chain. The recommendations also serve as bases for future research implications necessary for sector transformation and sustainable construction in KZN.
The need investigate career progression of female professional employees in the South African construction industry
Authors: Ndweni Mbalenhle P. , Ozumba Aghaegbuna O. U.
Published: February 2021

The purpose of the study is to investigate factors influencing career progression of female professional employees in the construction industry in order to identify challenges and suggest possible mitigations. An integrative review of purposively sampled literature on career progression is used to arrive at challenges to career progression faced by female professionals in the South African construction industry. The limitation of the study is its theoretical nature at this stage. Findings show that involvement of women in the construction industry has increased. However, women apparently still face challenges in progressing to senior positions in their careers. Some noted common factors include training, mentoring support, and networking. Implications of the study include the need to study factors influencing female career progression with the support of empirical data. There is also a need to examine the factors that act as barriers and analyse their nature in order to develop possible mitigations, which are also nuanced with the experiences of the subject population. The study forms a basis for understanding influencing factors and challenges to career progression of female professionals. This study is at its early stage of a more extensive research project and will be used as the foundation for empirical studies.
Analysis of construction worker’s demotivation that affect productivity in the South African Construction Industry
Authors: Jesumoroti C , Draai W
Published: February 2021

The research study was carried out on the investigation to the extent at which demotivation affect construction workers to perform higher levels of productivity. While worker motivation has been proven to improve productivity globally, motivation was rarely implemented in South African conditions. This study gauges the construction workers’ viewpoint on how motivational strategies can improve worker productivity. A pilot study was done in the preliminary phase to study in other to gain more insight into the study. A quantitative survey was used with structured survey for workers including electricians, earth workers, plumbers, bricklayers, and experts. Questionnaire was administered in Nelson Mandela Bay Metropole, South Africa at selected construction companies. Most prevalent in the findings of this study is the fact that the workers agreed that a lack of supervisory motivational techniques negatively impact their output. Research study hence finalize that managerial motivational strategies are required to enhanced construction workers’ productivity on a construction sites. Hence, there was suggested that supervisors use motivational communication, extrinsic rewards, intrinsic rewards and positive reinforcement for construction workers so as to increase their performance.
A Scientometric Review of Student Housing Research Trends
Authors: Simpeh Fredrick , Akinlolu Mariam
Published: February 2021

This paper presents a scientometric review of student housing studies; exploring the key authors and the collaborations among authors and countries, as well as the research trends with the aim of identifying gaps in this area of research where more studies is required. The VOSviewer software (version 1.6.13) was used for a Scientometrics review of 65 student housing publications from 2000 to 2020. The analysis focused on bibliographic coupling of countries, co-authorship of authors, citation of documents, and co-occurrence of keywords, which were further presented as network visualization maps. Scopus database was selected as the only data source. Therefore, the representation of publications presented in this study are limited to only one data source. The findings revealed that there is a satisfactory level of international collaboration in this research area. United Kingdom had the strongest link whilst Saudi Arabia had the weakest link. Both the keywords and documents citation analysis revealed three main trend of student housing research, i.e. residential satisfaction, post occupancy evaluation, and studentification. Gaps identified where more research is required include sustainable student housing, student housing safety and prioritisation of student’s requirement. This study provides invaluable information on the research trends in student housing studies. Thus, helping to identify gaps where more research is required.
Making course evaluation exercises count—a reprise
Authors: Babatunde O K , Mashigo A S
Published: February 2021

This paper builds on an earlier conference presentation at the West-East Institute, Harvard University in 2019. Following further critical dialogue on mass experimental online learning influenced by the COVID-19 pandemic, the now two authors sought to answer the question of how can educators make course evaluation exercises count? The objective was to assess the viability of reflective journaling as an alternative form of course evaluation. Consequently, the authors used a mixed-method approach to, firstly, analyze ordinal data collected from seventy-one (71) postgraduate engineering candidates (89% response rate) on their attitudes towards learning. Secondly, the authors analyzed the textual data on the candidates’ self- and educator-led initiatives to enrich their learning experiences. The findings revealed a paradox—the candidates hope to have gained in-depth knowledge at the end of their courses (topmost-ranked: mean = 4.704 and SD = 0.700) but do not attend most classes with questions in mind that they want to be answered (bottom-ranked: mean = 3.451 and SD = 1.072). Analysis of the textual data showed face-to-face lecture/class attendance and the overall course design as the most common student-led and educator-led approach, respectively. Finally, the authors discuss the practical and theoretical implications considering the burgeoning online education.
A comparative analysis of student housing security measures
Authors: Adisa S , Simpeh F
Published: February 2021

Security lapses have been identified as a problem in most on-campus Student Housing Facilities (SHFs) in South Africa. Thus, this paper investigates the security measures provided in the SHFs of two South African universities with the aim of identifying areas where improvements are required. The study adopted both qualitative and quantitative survey approach. Qualitative data was collected from the university health, safety, and environment officers of both universities whilst the quantitative data was collected by means of questionnaire from the students. Descriptive (mean score) statistics was used to analyse the quantitative data whereas thematic analysis was used for the qualitative data. The study found that the security measures provided in the SHFs of University B were better than those provided in the SHFs of university A. Although university B had a better provision, some lapses were identified such as inadequate Closed-Circuit Television (CCTV) and absence of weapon detector. In addition to these two lapses identified in university B, university A had lapses in the provision of access control, security patrol, electronics coded locks on door, and security alarm in most of the residences. Thus, security lapses identified in both institutions were inadequate CCTV and absence of weapon detector. The study provides empirical information that can help the university health and safety officers and facility managers to improve the SHFs security measures.
The role of the 4th Industrial Revolution (4IR) in enhancing performance within the construction industry
Authors: Keogh M , Smallwood J J
Published: February 2021

Construction continues to experience challenges in terms of a range of issues, namely an archaic process and activities, following procedures, data gathering and recording, monitoring, availability of skilled labour, and a declining interest in pursuing careers in the industry. Then, challenges are experienced in terms of performance relative to the project parameters of cost, environment, health and safety, productivity, quality, and time. Given the challenges and the advent of Industry 4.0, a study was conducted to determine the challenges experienced, performance relative to the project parameters, and the potential of Industry 4.0 to contribute to resolving the challenges. The study was quantitative in nature and entailed a self-administered questionnaire survey of medium to large general contractor members of the East Cape Master Builders Association (ECMBA) in the Port Elizabeth region. The findings include: respondents do understand Industry 4.0; a range of challenges, which negatively impact project and organisation performance, and the sustainability of organisations and the industry, are experienced in construction, and Industry 4.0 is perceived as having the potential to address the challenges experienced. Conclusions include that that there is: a need for improvement in performance in construction; potential to improve; a perceived need for the implementation of Industry 4.0, and a need for interventions to raise the level of awareness, and to integrate such technologies into built environment / construction education and training. Recommendations include: employer associations, professional associations, and statutory councils should raise the level of awareness relative to the potential implementation of Industry 4.0 in construction; case studies should be documented and the findings shared; tertiary built environment education programmes should integrate Industry 4.0 into all possible modules, and continuing professional development (CPD) should address Industry 4.0.
Analysis of risk occurrence in projects executed by small and medium sized contracting firms
Authors: Opawole Akintayo , Kajimo-Shakantu Kahilu
Published: February 2021

The performance of small and medium sized construction firms has attracted research attention in recent times because of the impact on sustainable economic growth. This study examined this category of firms as their performances in building project delivery are impacted by specific risk factors. The purpose is to provide empirical evidence that could enhance the choice of appropriate risk management approaches and improve the performance metrics of the projects executed by the firms. Primary data were obtained through a structured questionnaire targeted at 100 firms which is about 40% proportional sample of 245 registered small and medium contractors in Lagos state, Nigeria, as at 2016. A total of 53 questionnaires completed by; 17 engineers, 12 quantity surveyors, 10 architect, eight 8 builders and 2 project managers provided valid responses for the analysis. Quantitative data collected were analysed using mean ranking, factor analysis, and t-test. While the results show; mistakes, changes in scope of project, price fluctuation, importing and customs and security risk factors, as the most frequently occurring variables, they nonetheless indicate no significant difference in the ranking of the occurrence of the factors by the operators of both small and medium sized contracting firms. Although findings are limited to occurrence indices of the factors, risk impact models based on severity indices of the individual variables on project performance executed by this category of contractors can be developed based on the empirical findings. The study also highlights implications for risk assessment and choice of appropriate management techniques that could help in improving the performance metrics of the projects executed by small and medium sized category of contracting firms.
Assessment of management strategies for residual on-site related risk factors in educational institutional building projects
Authors: Adaralegbe O A , Opawole Akintayo , Kajimo-Shakantu Kahilu
Published: February 2021

The magnitude of variance between the projected and actual performance parameters could sometimes be very high, especially in projects which involve huge elements of risk. To avert this unfortunate experience, there is need for the adoption of efficient risk management strategy. This paper therefore presents the report of an investigation conducted on strategies adopted for managing site related risk factors which impact on the educational institutions’ building projects performance. A structured questionnaire was used to collect primary and archival data from 52 building contracting organizations who were in involved in the tertiary education building projects in Ekiti State, Southwestern Nigeria. A total of 39 valid questionnaires received were used for the analysis. Data obtained were analyzed using iinferential and descriptive statistics. Expected monetary value, risk break-down model and human reliability assessment were identified to have higher efficiency for reducing project completion time overrun. Meanwhile, sensitivity analysis, risk break-down structure and brainstorming were found to provide better degree of effectiveness for curtailing cost overrun. Key lesson learnt from the study is that practitioners can gain profound insight into onsite related risk management strategies suitable for building projects. The relatively small sample adopted limits the generalization of the findings. Notwithstanding, the study highlights implications for design of formalized risk management strategies specific to site operations in building projects.
Cash flow management by contractors
Authors: Koopman K , Cumberlege R
Published: February 2021

The paper focuses on various cash flow management techniques selected and incorporated by contractors into their daily processes and the effects of poor cash flow management on their business. A quantitative research approach was used using a web-based questionnaire. The questionnaire was distributed to all contractors registered with the Master Builders Association within the Eastern Cape Province. Results revealed that majority of contractors successfully implement cash flow management techniques and are therefore able to meet their monthly obligations. Respondents further agreed that late payments are detrimental in terms of their cash flow causing project delays. Increased capital expenses and higher levels of competition in the construction industry market, force the construction companies to consent to an increased number of risks, effectively ensuring their vulnerability to negative impacts on their cash flow and inevitably exposure to unforeseen events that are innate in any construction project. The study was limited to the Eastern Cape region, therefore reducing the targeted population and number of responses. The study investigated the competency level of financial management by building contractors with reference to the implications caused by poor financial management on the contractual parties involved within a project. The aim of the study was to deduce the extent to which contractors in the Eastern Cape implemented effective cash flow management techniques to sustain their businesses. The study highlighted the link between factors negatively impacting cash flow and its subsequent cause of failing contractors within the construction industry. The paper responds to the conference theme given that the effective cash flow management by contractors within their own firms and pertaining to construction projects, promotes the sustainability of the Built Environment.
Measuring health and safety performance of construction projects in South Africa
Authors: Khoza JD , Haupt TC
Published: February 2021

The purpose of this study was to develop a client-driven H&S rating model to be used by construction clients to improve their overall project H&S performance. The attitude of clients towards H&S is critical in the overall H&S improvement effort on construction projects. This hypothesis was tested and verified using Covariance-Based Structural Equation Modelling (CB-SEM). Using the framework of factors from previous studies, a survey method was adopted for collecting data for this study. Contrary to the findings of the previous studies, the final CB-SEM results suggested that the contractual H&S arrangement is the only construct which has a direct effect on project H&S performance. Mediation hypothesis testing was performed, and results were that attitude and selection of contractors based on their historical health and safety performance have an indirect effect of project health and safety performance. The study was limited to a selection of projects for a range of clients executed by a major construction contracting organization. The study highlighted the urgent need to change the traditional mind-set that H&S is the responsibility of the construction contractors alone.
Factors Affecting Students’ Learning in Civil Engineering Measurement
Authors: Tunji-Olayeni P P F , Kajimo – Shakantu K , Ayodele T O , Emmanuela KZ
Published: February 2021

The purpose of this study is to assess the factors affecting students’ learning in civil engineering measurement, with a view to enhancing students learning experiences and outcomes. The methodology adopted for this research was quantitative with the use of questionnaires distributed to 30 civil engineering students in their 3rd year, studying at a Nigerian university. The measurement of items in the survey questionnaire was based on a 5 point Likert scale. The data from the survey were analysed using descriptive statistics such as percentages and mean scores. The data from the survey were also presented in the form of pie chart and table. Teaching style was found to be the most significant factor affecting students’ learning in civil engineering measurement. Other significant factors were factors that had to do with the nature of the course which included difficulty with understanding the measurement process, measurement calculations, standard method of measurement (SMM), taking off sheet and terminology and acronyms. The findings also provided additional evidence to support a conducive learning environment and the use of teaching aids in enhancing learners’ experiences. The study focused only on civil engineering students from one university in Nigeria. More empirical evidence of the factors affecting students’ learning in civil engineering measurement can be obtained by considering other universities within and outside Nigeria. The findings place great responsibility on lecturers to improve their teaching styles. Moreover, the use of sufficient examples during teaching, and the use of 3D drawings such as Revit would greatly enhance the learning experiences of students in civil engineering measurement.
Usage of Local Knowledge in International Project Management: Case Study of Regional Waste Management Centre in Subotica, Republic of Serbia
Authors: Pevač D Plazina , Trivunić M , D’Amico L , Jakšić Ž , Stoilović O
Published: February 2021

International project management can largely depend on the initial parameters that international companies face when entering to new and unknown markets. Observing and using local knowledge in early stages of project development can minimize potential risks. This paper thus presents an example of the impact of perceiving or disregarding local knowledge during project implementation, as well as during the trial period of Regional Waste Management Centre (RWMC), executed by the international joint venture, in regards to the impact on the efficiency and effectiveness of the project cycle per Contractor. Through a causal loop diagram (CLD) the study shows that local knowledge should be an integral within the project implementation adding its success. This is mainly shown trough the parameters capability to enhance the reinforcing dominance of the system in a positive direction. By doing so a base of local knowledge can be formed whose inclusion or elimination from the project has direct influence of the overall success of said project. The data collected and analysed within this study, thus shows applicability to a new international project and serves as an inspiration for future project developments.
The impact of tree clusters on air circulation and pollutant diffusion-urban micro scale environmental simulation based on ENVI-met
Authors: Jing Lili , Liang Yuan
Published: February 2021

For urban planners, trees play a role in improving landscape quality, but their impact on urban ventilation is often ignored. By using the three-dimensional microclimate model ENVI-met, this article simulates 14 situations with different variables, aims to re-examine the impact of vegetation cover on aerodynamic effect. The results show that trees have a resistance effect on air flow, Especially the ratio of tree spacing/canopy width related to the continuous vortex area have a significance impact on wind speed, which is needed to be considered in urban planning of vegetation layout. Moreover, the distinguished theories under both conditions whether there is buildings or not are analysed, inspiring the planners and researchers to consider the relationship and discrepancy between different scales.
Design of modular constructed wetland and its effect on rural domestic sewage treatment
Authors: Changsong Cong , Mingsen Wang , Li Jin , Ye Tian
Published: February 2021

According to the characteristics of large amount and scattered discharge of domestic sewage in rural residential environment, a rural domestic sewage treatment system based on modular constructed wetland was designed. The wetland is composed of three modules with a treatment scale of 30 m3/d. The plants are Arundo donax and Typha, and three kinds of filter media are selected to fill the substrate. The treatment capacity and treatment effect of the modular constructed wetland were studied through experiments. The results showed that the modular constructed wetland had a good treatment effect on sewage, and the average removal rates of BOD5, COD, SS, NH3-N, TN and TP were 83.3%, 83.5%, 90.5%, 70%, 66.9% and 68.3%, respectively. The treated water quality can meet the first class standard of water pollutants discharge standard for rural domestic sewage treatment and disposal facilities (DB37/3693-2019) of Shandong Province. The modular constructed wetland can be used to treat rural scattered domestic sewage with strong applicability, flexibility and feasibility.
Study on pore network model of porous media hydrate permeability
Authors: Zhang Qingge
Published: February 2021

Considering the influence of hydrate on fluid flow in porous media, the relationship between hydrate saturation and absolute permeability of porous media is studied by using pore network model. The absolute permeability of hydrate free porous media is calculated and the convergence is studied. The absolute permeability of hydrate bearing porous media is calculated, the phase equilibrium migration is studied, and the pore network model of hydrate porous media system is calculated. The results show that: (1)when the throat number in the pore network model is greater than 3000, the calculation result is relatively stable; (2)under the condition that the throat diameter follows the log-normal distribution, the permeability decreases faster with the increase of the standard deviation; (3)the calculation results of the network model are consistent with the experimental data, which proves its feasibility to a certain extent.
Effects of alloying elements on the dissolution and diffusion of Bi in Sn: A first-principles study
Authors: Sun Lu , Yan Jiasi , Wang Limin , Xiao Wei
Published: February 2021

Interfacial Bi segregation in Sn-based solders is a critical issue that affects the reliability of solder joints. Doping alloying elements into Sn-Bi solders is considered as a potential way to improve the Bi precipitation. We provided insights into the mechanism of Bi segregation at the atomic scale, by calculating the dissolution and diffusion energies of Bi in the Sn bulk. Importantly, we investigated the effects of alloying elements on the Bi dissolution and diffusion, which varies much with element species. The addition of elements such as Pt, Pd, and Au could enhance the dissolution and weaken the diffusion of Bi in the Sn bulk, thus suppressing the interfacial Bi segregation to some extent. However, other elements such as In, Ag, Sb, and Ga have slight impacts on the dissolution and diffusion of Bi. The bonding characters between the third elements, Bi, and Sn atoms explain different influences of alloying elements on Bi segregation in Sn-based solders.
The Temporal and Spatial Shift of Vertical Quantity and Source of the PHC Content
Authors: Yang Dongfang , Li Haixia , Lin Dong , Ren Haoyuan , Wang Qi
Published: February 2021

According to the investigation data of PHC in Jiaozhou Bay in May, August and October, 1992, this article shows the source of PHC content in both surface and bottom of Jiaozhou Bay and the temporal and spatial shift of vertical content by comparing the horizontal and vertical changes of PHC content and the PHC content in the surface and bottom. Consequently, in May, August and October, the results from subtracting PHC content in surface and bottom was between -0.004 – 0.028 mg/L, which indicated that the PHC content in both surface and bottom was close. In May, the difference of PHC content between the surface and bottom was -0.004 – -0.020 mg/L, both were negative, in the central and estuary waters of Jiaozhou Bay. In August, the difference of PHC content between surface and bottom layer of all stations in Jiaozhou Bay was 0.007–0.021 mg/L, which was positive. In October, the difference of PHC content between the surface and bottom layer of all stations in Jiaozhou Bay was 0.010–0.028 mg/L, which was positive. On the spatial scale, with the PHC content far away from the source, there are spatial changes of PHC content. In the center of the Bay and the northern part of the bay mouth, the PHC content of the surface layer is less than that of the bottom layer. In August and October, the difference of surface and bottom layer contents of all stations in Jiaozhou Bay was positive, showing that the PHC content of surface layer was higher than that of bottom layer. On the temporal scale, with the change of time, the source of PHC content underwent changes, showing the temporal changes of PHC content in surface and bottom. From May to August, the source of PHC content in the transportation changed. And the PHC content in the surface layer and the bottom layer in the transportation decreased. From August to October, the source of PHC content in the conveying system changed further with more PHC content in the surface layer and in the bottom layer.
Research on Micro-Analysis System of Dye in Water Sample Based on Magnetic Nano-TiO2
Authors: Xiaoting Zhu , Heyong Cheng , Meiying Ye
Published: February 2021

Magnetic Nano-Photocatalytic Material (NMPC) helps separate and recover nano photocatalyst in water treatment. However, it is rarely reported that a photocatalyst can be separated online in photocatalytic microreactors. In this paper, a typical dye methylene blue was photocatalytically degraded in glass microfluidic chip by using Fe3O4@ SiO2@ TiO2 (FST) as the magnetic nanocatalyst, the UV-LED as the ultraviolet light source, and ultraviolet-visible spectrophotometer as the detector. The FST was easily separated by an external magnetic field, thereby realizing rapid online detection of methylene blue. During the preparation of FST, the hydrothermal method was used to treat the obtained FST nanoparticles in 100°C boiling water bath, and the titanium-iron ratio was optimized, so as to obtain FST nano-photocatalyst with high photocatalytic performance and good dispersibility. With 1.0 g/L FST/8%H2O2 being the catalytic oxidation system, the sample flow rate being 300 μL/h, the reaction temperature being 45 °C, the degradation rate of methylene blue has reached 100%. It only took 25 min to complete one measurement. The FST consumed per measurement was only 125 μg. The RSD of the photodegradation rate was 2.5% (n=9).
Products characterization for fast in-situ catalytic pyrolysis of bio-oil over Ni/Al2O3
Authors: Deng Zengtong , Wang Yi , Hu Song , Su Sheng , Jiang Long , Xiang Jun
Published: February 2021

Pyrolysis is a promising technology for bio-oil utilization. However, bio-oil is thermally unstable and easily coking due to the complicated components and their interactions. This study developed an in-situ catalytic pyrolysis method for bio-oil over Ni/Al2O3. The results of product distribution and aromatic structures were investigated to elucidate the influence of catalyst participation and droplet sizes of bio-oil. The nickel catalyst can effectively decrease coke yield and increase gas yield at the studied condition (800 °C fast pyrolysis). Small droplets that lead to a higher heating rate would promote severer secondary reactions which lead to repolymerization. The catalyst would provide adsorptive points that help small fragments to be cracked and result in large fragments polymerizing.
Loss-of-function of vacuolar-type H+ pyrophosphatase gene lead to reduce in stomatal aperture and density
Authors: Gao Ma-ye , Liang Jin , li Hao , Zhong Rong , Di-an Ni
Published: February 2021

Transgenic plants over-expressing vacuolar H+ type pyrophosphatase (V-PPase) gene were reported to display drought resistance, reduced vacuolar pH and raised stomatal conductance. To further understand the role of V-PPase on stomatal regulation, loss- and gain-of-function approaches were combined for analysing relationship between stomatal aperture and V-PPase gene expression. Homozygous mutants of this gene were isolated by polymerase chain reaction (PCR) method. BCECF-AM fluorescence probe was used for detecting cellular pH. The result here indicated that Arabidopsis plant lines over-expressing of V-PPase gene displayed raised stomatal aperture. Both of stomatal aperture and density of homozygous vpp mutants were less than that of control plants. In addition, cellular pH of guard cells in vpp mutants was higher than control evidently. In general, our results suggested that V-PPase activity regulates stomatal aperture by changing guard cell pH.