bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Analysis of Ride Comfort Quality for High-speed Railway Vehicles
Authors: Huang Jiangwei , Chen Sijie
Published: November 2020

In order to study the vehicle comfort, in this investigation, the empty dynamic test is carried out on the vehicle operating line, and the conditions of air spring inflated and air spring deflated are considered respectively. On condition of air spring inflated, the test speed of vehicle starts from 60 km/h, with a speed step of 20 km/h, up to 140 km/h. On condition of air spring deflated, the test speed of vehicle starts from 40 km/h, with a speed step of 20 km/h, up to 100 km/h. Then the vehicle body vibration acceleration is measured, and data is carried out processing through the standard EN12299-2009 Railway applications – Ride comfort for passengers – Measurement and evaluation. The results of test and data processing show that: under the normal condition of air spring, the maximum values of ride comfort index of motor (D1) and trailer (M1) are 1.43 and 1.70 respectively, both less than 2.5; under the condition of airless spring, the maximum values of riding comfort index of motor (D1) and trailer (M1) are 1.94 and 2.23, both less than 3.0.
Finite element analysis and testing on the vibration mode of small grinding carriage in high-efficiency CNC grinding machine
Authors: Zheng Dateng , Zhang Qing , Zhang Jing , Yao Haibiao , Yin Sanfeng
Published: November 2020

The small grinding carriage is a key component of the high-efficiency computerized numerical control (CNC) grinding machine. The machining of the small grinding wheel is the last process of the workpiece on the grinding machine, and its vibration performance has an important influence on the grinding precision. A novel low vibration grinding carriage using finite element analysis method (FEM) was designed to validate its vibration performance before producing. In this study, the finite element model of the small grinding carriage was established. The finite element calculation was performed using the Block Lanczos algorithm, and the first natural frequency of the small grinding carriage was 283.2 Hz. Besides, the experimental modal analysis method of ambient excitation was used to test and analyze the small grinding carriage assembled to a grinding machine. The modal parameters of the system structure were identified based on the theoretical auto power spectrum. The first five natural frequencies and damping ratios of the small grinding carriage were obtained. The accuracy of the recognition results was verified using the modal judgment criteria. The two methods cross-validated the structure design of the small grinding wheel, which can avoid resonance during machining. The results provided in this paper can serve as a reference for the subsequent structural optimization design.
Simulation and Research of Aerospace Material Milling Based On ABAQUS
Authors: Zhang Yanzhong , Huang Xiaohua
Published: November 2020

In this paper, ABAQUS simulation software is used to establish the model of the tool and the blank. Through the simulation of the single tooth milling process of 2024 aviation aluminum alloy material, the temperature and stress distribution cloud diagram, the cutting force curve are obtained. The effects of various cutting factors on the milling temperature are studied using simulation methods. The study found that the milling temperature increased with the increase of the axial depth of cut, radial depth of cut, cutting speed, and feed per tooth, among which the cutting speed had the greatest effect on temperature.
ROS-responsive probes for low-background optical imaging: a review
Authors: Xu Yan , Yang Weitao , Zhang Bingbo
Published: November 2020

Optical imaging is a facile tool for visualizing biological processes and disease progression, but its image quality is largely limited by light-induced autofluorescence or background signals. To overcome this issue, low-background optical-imaging techniques including chemiluminescence imaging, afterglow imaging and photoacoustic imaging have been developed, based on their unique working mechanisms, which are: the detection of light emissions from chemical reactions, the cessation of light excitation before signal collection, and the detection of ultrasonic signals instead of light signals, respectively. Stimuli-responsive probes are highly desirable for improved imaging results since they can significantly reduce surrounding interference signals. Reactive oxygen species (ROS), which are closely implicated in a series of diseases such as cancer and inflammation, are frequently employed as initiators for responsive agents to selectively change the imaging signal. Thus, ROS-responsive agents incorporated into low-background imaging techniques can achieve a more promising imaging quality. In this review, recent advances in ROS-responsive probes for low-background optical-imaging techniques are summarized. Moreover, the approaches to improving the sensitivity of probes and tissue penetration depth are discussed in detail. In particular, we highlight the reaction mechanisms between the probes and ROS, revealing the potential for low-background optical imaging.
Recent California tree mortality portends future increase in drought-driven forest die-off
Authors: Madakumbura Gavin D , Goulden Michael L , Hall Alex , Fu Rong , Moritz Max A , Koven Charles D , Kueppers Lara M , Norlen Carl A , Randerson James T
Published: November 2020

Vegetation tolerance to drought depends on an array of site-specific environmental and plant physiological factors. This tolerance is poorly understood for many forest types despite its importance for predicting and managing vegetation stress. We analyzed the relationships between precipitation variability and forest die-off in California’s Sierra Nevada and introduce a new measure of drought tolerance that emphasizes plant access to subsurface moisture buffers. We applied this metric to California’s severe 2012–2015 drought, and show that it predicted the patterns of tree mortality. We then examined future climate scenarios, and found that the probability of droughts that lead to widespread die-off increases threefold by the end of the 21st century. Our analysis shows that tree mortality in the Sierra Nevada will likely accelerate in the coming decades and that forests in the Central and Northern Sierra Nevada that largely escaped mortality in 2012–2015 are vulnerable to die-off.
Diffraction of Wigner functions
Authors: Creagh Stephen C , Sieber Martin , Gradoni Gabriele , Tanner Gregor
Published: November 2020

We describe the contribution of diffractive orbits to semiclassical approximations of Wigner function propagators. These contributions are based on diffractively scattered rays used in the geometrical theory of diffraction (GTD). They provide an extension of well-established approximations of Wigner-function propagators based on rays that propagate by specular reflection and refraction. The wider aim of this approach is to allow for diffractive mechanisms to be accounted for in Eulerian approaches to ray-tracing simulations. Such approaches propagate densities of rays rather than follow rays individually. They promise to be a more efficient means of performing ray-tracing simulations in complex environments with applications in, for example, planning of wireless signal coverage for mobile communication networks.
Synthesis and Size Control of Aluminum Nanoparticles using Solution Plasma Process
Authors: Liew B Y Y , Ranjit M S , Julaihi M R M , Yek P Y N , Shibayama T
Published: November 2020

This research was conducted to investigate the various control techniques to vary the size of aluminum nanoparticles through solution plasma process, specifically the submerged glow-discharge plasma process. Aluminum nanoparticles have received many attention due to their unique combustion, resistance and superhydrophobic properties. A lab-scale based submerged glow-discharge setup has been constructed to produce the nanoparticles. Different concentration of potassium carbonate electrolyte (0.1M – 0.5M) and cathode submerged length (50 mm – 100mm) were used in this study. The results were viewed and analyzed using scanning electron microscopy. As the major results showed that the diameter size distribution ranges from 80nm to 2µm. Higher concentrations have shown to produce smaller nanoparticles due to the overlapping of electron beams on the cathode surface. Also, shorter cathode submerged lengths have resulted in larger-sized nanoparticles.
Application of variable geometry turbine turbochargers to gasoline engines- A review
Authors: Dasgupta S , Sarmah P , Borthakur P P
Published: November 2020

An ideal engine today is considered to be one with low emission, low fuel consumption and high specific power output. Engine downsizing by turbocharging provides an answer toall the three. Though the traditional problems of poor low end torque and inadequate transient response have been overcome to a great extent using variable geometry turbine turbocharger in diesel engine, the application of variable geometry turbine turbocharger is in quite a nascent stage when it comes to gasoline engine. This article primarily describes all the important aspects of application of VGTs to gasoline engines right from when VGT’s were restricted to only very expensive research prototypes to the very recent application in cost sensitive production engines. Also at the same time,it highlights the need and development in the flow range of the turbocharger compressor, addressing problems of choke and surge in the turbo chargers compressor.
Direct Fermentation of Oil Palm (Elaeis guineensis) Trunk Sap to Bioethanol by Saccharomyces cerevisiae
Authors: Norhazimah A. H. , Siti F.M.N. , Aida M. , Dilaeleyana A.B. , Nur Shahirah M. A.
Published: November 2020

Oil palm agricultural biomass has a great potential for biofuel production due to its abundance and less pretreatment needed. In this study, bioethanol production from oil palm trunks sap was carried out by using yeast Saccharomyces cerevisiae. The suitability of the oil palm trunk sap for bioethanol production was tested by investigating the relationship between the oil palm trunk sap concentration and ethanol produced. The fermentation was conducted in static condition and without pH adjustment using 60, 80, and 100% oil palm trunk sap concentration. Results showed that the highest bioethanol production rate was achieved for 100% oil palm trunk sap (1.033 g/L.h), followed by 80% (0.744 g/L.h), and 60% (0.645 g/L.h). These results were influenced by the presence of sugars in the initial sap, suggesting that high substrate concentration does not inhibit bioethanol production. Therefore, the oil palm trunks sap showed significant potential as a renewable feedstock for the production of bioethanol without dilution.
Experimental Investigation of the Flexural Behavior of Steel Fiber Reinforced Concrete
Authors: Karzad A S , Al-Sadoon Z , Leblouba M , Maalej M
Published: November 2020

This research study is conducted to investigate the flexural behaviour of steel fiber reinforced concrete (SFRC) prisms incorporating different types and volume fractions of steel fibers, various grades of concrete, and different specimen depths, all tested under displacement control mode using four-point loading configuration. Two types of steel fibers (hooked end and straight) were incorporated into the concrete mixes at two different dosages (1% and 2%). Concrete mixes with compressive strengths of 40, 50, and 70 MPa were used to cast the samples. Specimen depth was also among the test variables, where prisms of depth 100, 150 and 200 mm were tested to study the size effect on the flexural behaviour of SFRC. Test results indicated that for the straight-end steel fibers, the increase in the fiber volume fraction from 1 to 2% had a noticeable effect on both flexural strength (or Modulus of Rupture, MOR) and associated prism mid-span deflection. However, for the hooked end steel fibers, there was only a limited increase in the same measured values due to reduced workability of the SFRC fresh mix. The test results also have shown that the increase in the concrete compressive strength had only a modest effect on the average MOR value, but a noticeable effect on average mid-span deflection at peak load. The latter was attributed to the relatively long length and the hooked end geometry of the steel fibers. Finally, test results revealed that specimen depth had an impact on the measured flexural strength, where increase in specimen depth was associated with reduced MOR values, a phenomenon that is commonly referred to in the literature as size effect.
Photo-voltaic Powered Electric Vehicle Fast Charger
Authors: Lai C P Y , Law K H , Lim K H
Published: November 2020

In the last years, dominant usage of petroleum-based transportation and consumption of fossil fuels results in greenhouse gas (GHGs) emissions into the atmosphere which causes negative impacts across the globe. As the situation worsens, more people are motivated towards opting for electrified transportation. However, there are still a lot of challenges to be overcome with one of the main issues concerning the development and availability of fast charging technologies in electric vehicles (EVs). To decrease high energy demand from the grid, usage of renewable energy systems (i.e., photo-voltaic) to fast charge EVs are preferred. In this paper, high performance DC-DC boost converter controlled by PI controller is proposed with the objective to mitigate the current state of fast charging and environmental problems. The proposed converter is able to generate different output power level based on the desired preset reference voltage value. All simulation results are documented to verify the proposed photovoltaic (PV) powered EV fast charger. For simplicity, EV batteries are being replaced with one resistor as the load whereas PV panels are used to generate input power for the converter.
Surface Engineering of Titanium Using Anodization and Plasma Treatment
Authors: Mallaiah Manjaiah , Kumar Gupta Ravi
Published: November 2020

Ti64 alloy is a well-known material for biomedical applications due to high corrosion resistance and biocompatibility properties. Surface properties of implants plays a vital role in bone and cell growth in the human body. With the anodization process, we can increase the surface porosity, which will be adequate for surface fascination of the implant screw to the bone and appropriate mechanical properties. Hence, the present study attempted to improve the surface properties of Ti64 by anodization and plasma treatment that may be promising method to increase the biocompatibility of Ti materials. Anodization process is the cheapest one to improve the surface properties of Ti alloy and riskless process. To intensify the open pores on the Ti64 surface plasma treatment was performed. Also, the aim of this study was to improve the aesthetic appearance of the dental implants and reproduce interference of colours. With the help of UV-VIS spectrophotometer the colour and spectral reflectance were investigated. The oxide layer thickness, chemical composition and nanosurface roughness was measured. These results suggests the surface modification of Ti64 alloy by anodization can produce interference of colours and are dependent on the applied voltage, oxide layer thickness. The surface oxidation consisting of anatase and rutile phase and change in nanosurface roughness, may improve the biocompatibility of Ti64.
The Mechanical and Thermal Properties of Polyurethanes/Precipitated Calcium Carbonate Composites
Authors: Lai Q Y , Yuhana N Y , Fariz S , Otoh M Z
Published: November 2020

The properties of polyurethane containing precipitated calcium carbonate (PCC) were studied. The PCC were produced from acetylene gas waste, and its usage as filler material for polymer were explored in this study. Present findings suggested the addition of 5 per hundred gram of PU(phr) significantly increases the shore A hardness to 39.2, in addition to improve the degradation mperature and specific gravity with decrease in water and oil absorptions capacity. The addition of 5 phr PCC to polyurethane improves the material structure and the morphology as calcium carbonate were dispersed when observed using microscopes. This research extends our knowledge of the addition of PCC to strengthen the mechanical and thermal properties of polyurethanes.
Finite Element analysis: Predicting cutting force in turning of Inconel 625 using ceramic tools
Authors: Reddy M M , William L C S
Published: November 2020

Inconel 625 is a unique material due to its characteristic properties of high strength at high temperatures, high corrosion and oxidation resistance. These unique properties thus pose a challenge to machine Inconel 625. Characteristics of work hardening in Inconel 625 generates high cutting force which results in poor surface finish and reduce the performance of cutting tool. Two-dimensional turning operation simulation is considered to evaluate cutting force in this research study. Box- Behnken design of experiment under Response Surface Methodology is used to identify the cutting force with 15 different combinations of cutting speed, feed rate and depth of cut parameters. Predictive mathematical model for cutting force is developed and obtained. From Analysis of Variance (ANOVA), depth of cut had significant influence on cutting force followed by feed rate and cutting speed. Optimization of cutting parameters was carried out and it is recommended that a low combination of depth of cut and feed rate should be selected with a high cutting speed to achieve minimum cutting force. The effect of rake angle on cutting force was investigated for ceramic cutting tools.
Telerobot: Failure Detection Using Imaging Technique for Piping Internal Surfaces
Authors: Hussein H.M.A. , Ramadan Aya A. A. , Kumar Gupta Ravi
Published: November 2020

Pipelines are the energy lifelines of almost every activity of everyday life. It is a safe way of transporting water, gas and oil over long distances. It is also the most practical way to deliver oil and gas across countries as being an extremely safe and economically viable solution to transport energy. Cracking and corrosion on the external and/or internal surfaces of in-service pipes, reduces the integrity of the material and potentially reduces the service life of the transportation system and equipment. Defects in pipelines may have various forms and may be initiated by one or more mechanisms potentially resulting in corrosion and/or cracking. In this paper we propose a system that detects the internal cracks in pipelines through a telerobot which can be inserted into the pipelines and detects the internal Failures (cracks) through a special modern high resolution digital camera and image processing techniques. The telerobot is a programmable and can be controlled as per the requirements such as speed and direction of the telerobot and sensors using mobile application and can be connected to a computer and smart phone. The telerobot captures a high definition images and also captures the precise location. These images are transferred to a computing facility for the analyses and to detect cracks.
Influence of flow limiter and grain shape factor of sand particles on erosion activity in pipeline
Authors: Tang Genevieve A T K , Foo Henry C Y , Tan I S , Yeong Y F , Lam M K
Published: November 2020

Erosion has been evaluated as the main cause of failure in pipework. The focus of this work is the effect of erosion activity on two-phase flow (solid-liquid) condition. Pressure distribution of liquid flow, velocity profile of liquid flow and trajectories of sand particles are scrutinized. Based on the experimental data, different limiter pipeline was simulated to validate the data and an overall grain shape factor of 0.265 was obtained. From the qualitative and quantitative analysis of grain shape factor (GSF), it was identified that the 75 % of sand are composed of high sphericity particles (GSF=0.2), 25 % of sand composed of slightly lower sphericity particles (GSF=0.45). For the simulation work, the fluid flow rate, grain shape factor and sand concentration is altered ranging between 25 litres/s to 50 litres/s, 0.2 to 1.0 and 0.5 % to 1.0 % respectively. Through ANOVA analysis and it demonstrated the significant influence on erosion activity in descending order (fluid flow rate > shape factor > sand concentration). After numerical optimization, the minimum erosion activity on limiter was obtained by obeying the settings of fluid flow rate, shape factor and sand concentration as 50 litres/s, 0.2 and 1.0 % respectively.
Performance evaluation of horizontal flow constructed wetlands as primary and secondary treatment for university campus wastewater
Authors: Yong Tan Yee , Tang Fu Ee , Lee Ing Ho Carrie , Shu Zhen Wong Madeline
Published: November 2020

Horizontal flow constructed wetland (HFCW) is an attractive green technology for wastewater treatment. In the present study, four laboratory-scale HFCWs were constructed to serve as the primary and secondary treatment of university campus wastewater. The effect of hydraulic residence time (HRT) and pre-aeration of influent were investigated. The experimental results demonstrated that the wetland vegetation played an important role in the oxygen restoration and the influence of pre-aeration was minor. In the primary treatment, effective removals of TSS and NH4-N were observed. However, the treatment of BOD and NO3-N were insignificant due to the low influent concentrations. As for secondary treatment, the HFCWs effectively reduced the concentrations of BOD, NH4-N, and NO3-N in the effluent from the Intermittent Decanted Extended Aeration (IDEA) plant. The effluent quality of all HFCWs complied with the Standard A sewage discharge. Longer HRTs brought a positive effect to the removals of organic matter and nitrogen.
Dynamic Simulation of Hydrogen Iodide Decomposition in Catalytic Multi-Tubular Reactor
Authors: Nandong Jobrun , Sirajul Akmal , Mohd Noraini
Published: November 2020

Sulfur-Iodine thermochemical cycle process has been considered a promising method to generate hydrogen from water. One of the main limitations of this process lies in the hydrogen iodide decomposer section, which requires substantial amount of heat at high temperature. The present study analyses the heat transfer limitation effect on the performance of hydrogen iodide decomposition in a multi-tubular catalytic reactor by means of dynamic simulation. The extensive numerical simulation shows that the inlet temperature heating medium (Helium gas) should be at least 700°C so to enable at least 90% conversion when the inlet molar fraction of hydrogen iodide is 0.6. Lowering the inlet heating medium will require the reduction in the inlet molar fraction of hydrogen iodide in order to keep the conversion at 90% and above.
Numerical analysis of erosion pattern on pipe elbow bend with swirling flows
Authors: Yam K S , Roy S , Lee V C C , Law M C
Published: November 2020

Abrasive solid erosion is a common issue faced in many industrial applications and can incur significant loss to production efficiency. In a piping system, the bends are generally the most vulnerable to the abrasive erosion due to the abrupt change of flow. Reducing the erosion at the bend is key to industries for safety purpose and ensure equipment longevity. This research focusses on the effectiveness of utilizing the swirling flow in reducing the erosion rate at the elbow bends. Numerical approaches are adopted to systematically evaluate the impact of the degree of swirling in the flow on the erosion reduction at the elbow. The results demonstrate the promising prospect of the swirling flows as a mechanism to control the erosion at the pipe elbow.
Supply Chain Performance Analysis With Data Envelopment Analysis in TBBM PT. Pertamina Boyolali
Authors: Hanif Z , Kristy P , Utami M W D , Yuniaristanto  , Sutopo W
Published: November 2020

PT. PERTAMINA TBBM Boyolali is a supplier of fuel oil in the form of premium, pertamax and diesel. The company should distribute fuel products using tank cars with operating areas covering Boyolali, Surakarta, Karanganyar, Sukoharjo, Sragen, Klaten, Wonogiri, Ngawi, Pacitan, Magetan, Ungaran, Semarang, Salatiga, Purwodadi, and Blora. An efficient supply chain is needed to provide the right products and services, with the specifications needed, in the right place and to the right customers. This article aims to find out and analyze the efficiency that occurs at operational TBBM Pertamina Boyolali and to find out the variables that most influence supply chain performance to be analyzed and improved so that improvements in supply chain performance can be more focus and optimal. The Decision-Making Units (DMUs) stated in this article are the period of supply chain activities from January 2018 to November 2018 at TBBM Pertamina Boyolali, the number of DMU is 11 DMUs. Supply Chain Operation Reference (SCOR) method with responsiveness, flexibility, and reliability attributes is used to measure Supply chain performance. To analyze supply chains efficiency, this article applies input-oriented DEA CCR (Charnes, Cooper, and Rhodes) model which considers linear relationships in its input and output. Data Envelopment Analysis (DEA) is a strong tool for measuring the efficiency of the DMUs and does not need to normalize indicator values that have different dimensions. The software used for processing data in this article is Banxia Frontier Analyst 4.2. This article provides suggestions for improving cash-to-cash cycle time, lead time, and flexibility for more efficient fuel distribution.
Six Sigma Application to Minimize Castor 5 Inch Scrap Material in EOP Warehouse: A Case Study
Authors: Fajrianto A , Asnan M H I N , Khofiyah N A , Sutopo W , Yuniaristanto
Published: November 2020

Case study in this research at PT. Mega Andalan Kalasan, which one of the manufacturing companies engaged in manufacturing hospital equipment that often has problems regarding the quality of materials stored in warehouses. The problem is often found in the 5 Inch castor material that becomes scrap and incurs costs so that waste occurs. Based on data from April 2018 to September 2018, the percentage of scrap material is increasing every month from 1.44% to 1.77%. Due to these problems, the purpose of this research is to minimize the 5 Inch castor material which is a scrap to avoid waste costs in the Export Oriented Product Warehouse Unit of the company. The methodology in this study uses the Six Sigma method, namely by implementing the Define, Measure, Analyze, Improve, and Control (DMAIC) stages. The results obtained are the most dominant cause of scrap castor 5 Inch material is storage of material on a rack that is not organized with an RPN value of 240. Thus, it is necessary to make improvements to minimize the scrap castor 5 Inch material by conducting a routine briefing by the PIC Area Warehouse Unit Export Oriented Product before operational activities begin.
Redesign Determination of Plat Raw Material Supplier with Analytic Hierarchy Process (AHP) Approach: A Case Study
Authors: Hidayati K A , Rosanti A A , Khofiyah N A , Sutopo W
Published: November 2020

PT. XYZ is a company in the newspaper industry. The selection of suppliers so far is only based on the price offered and the promised delivery speed. The price offered by the supplier is also influenced by the exchange rate of the rupiah against the dollar resulting in price fluctuations in the purchase price of raw materials. Even though the price of raw materials has increased, newspaper prices have remained the same, and to avoid this problem, the company has supplied raw materials from many suppliers. The company has made good cooperation with several suppliers, but does not yet have the right supplier selection method and can be applied with a good planning process. Therefore, companies need to select suppliers with the right methods so that raw material orders are optimally fulfilled and get the best suppliers who can work together in the long run. In this study, the determination of the best suppliers is carried out on the raw material of the plate as well as important criteria in the selection of these suppliers . Data collection is done using interviews, questionnaires, and literature studies. Based on the results of data collection, among others, the purchase price, delivery time, maximum number of orders, the level of disability, and the distance of the supplier with the company. Data processing uses one of the MCDM (Multi Decision Making Criteria) methods, namely AHP (Analytic Hierarchy Process). With the results of supplier one being designated as the best supplier. This can be known with the highest final value in the final AHP calculation, with a value of 3.95643, and the criteria most considered in determining suppliers is the bid price.
Aggregate Planning Method as Production Quantity Planning and Control to Minimizing Cost
Authors: Nugraha I , Hisjam M , Sutopo W
Published: November 2020

Production planning is very important in a production because it is related to the amount of fluctuating consumer demand in each period. If there is a product shortage will cause consumer demand cannot be fulfilled so the company loses profits and commitment from customers who have trusted. However, if the excess production in a certain period there will be a buildup of products that are generated and will result in high storage costs of finished products and waste of product storage. Products that often occur in fluctuating demand is wheat flour products. Based on observations at PT. Bulog, the authors provide an analysis to overcome the problem of fluctuating demand at PT. Bulog with aggregate planning methods. Based on forecasting results that have been obtained in the previous period wheat flour demand data at PT. Bulog, we will determine the quantity and the future production time for wheat flour products. Production planning is a very important activity of all production activities of a company. Based on the calculation of aggregate planning that has been done using the company’s demand and production data PT. Bulog in the previous period found that the best method that can be used in the company’s production process is the chase strategy method, this method is used by increasing or reducing the number of workers based on the number of consumer demand. By using a chase strategy, the costs used by the company are less when compared to other methods. Costs to be incurred based on the selection of the best method for the product “Tepung Terigu Kita” is IDR 341,857,000.00.
A review on sustainable metrics for Sustainability Measurement in Supply Chain
Authors: Lsaputri V H , Hisjam M , Sutopo W
Published: November 2020

This research analyzes the performance measurement in sustainable supply chain using sustainable triple bottom line aspects, namely environmental dimension, social dimension, and economic dimension. The analysis process is accomplished for 40 articles, which are from Scopus website related to sustainable supply chain. The focus in analysis process is the sustainable dimension that has been used in the previous research. Furthermore, the other focuses are the analysis processes about the journal name, organizations that fulfill the performance measurement, the utilized approach, and the type of research. Then, in the final research, there will be explanation about the metric that is utilized to be a tool for performance measurement of sustainable supply chain in the organization.
Evaluation of practicality of virtual design and construction (VDC) with 5D building information modelling (BIM) through a case study
Authors: Lee M L , Cheah W T , Lau S H , Lee X S , Abdullahi A M , Wong S Y
Published: November 2020

Virtual design and construction (VDC) is defined as the use of multi-disciplinary performance models for the purposes of design-construction projects. The use of VDC in construction projects enables the stakeholders to communicate and visualize the buildability and construction sequence which will impact on a project’s success in terms of delivery time and cost. This case study investigated the process of integrating different dimensions of information such as time scheduling (4D) and cost estimation (5D) with a 3D model to simulate a 5D Building Information Modelling (BIM) process. The study explored the application of VDC with 5D BIM for a commercial building, namely Universiti Tunku Abdul Rahman (UTAR) Sungai Long City Campus. Through this case study, it enables comparisons of a virtual model and an actual construction in order to evaluate the advantages, practicality, and limitations of the VDC applications. The 5D model provided comprehensive information to manage the complex design-construction process by considering its timeline and cost. Six modelling stages were undertaken, namely inputting and modelling, clash detection test, time scheduling, quantification and cost estimation, virtualization, and walkthrough of the model. The results revealed that the practicability of the 5D BIM was influenced by the modelling effort, inter-operability, information output and limitations. The study also showed that VDC with 5D BIM significantly reduced the technical barrier for clients to participate in construction project, thus increasing the clients’ satisfaction of the works by bridging the gap of perception and actual outcomes from the construction.
Aurubis iron-silicate fines: universal sustainable construction material: a state-of-the-art review
Authors: Manolova E
Published: November 2020

This article brings together a lot of research information that deals with iron-silicate fines (ISF), as a basic by-product produced by the copper plant of Aurubis, located in Bulgaria. As a rare material, produced only in couple of plants in the world, ISF has a wide variety of applications due to its specific physical, chemical and mechanical characteristics. Well known for decades by the clinker cements industry, nowadays Aurubis presents a wide variety of new perspectives for creating green and sustainable building materials out of ISF. Sustainability in the construction sector is mostly referred to as zero waste scenarios related to the use of recycled and secondary materials (RSM). Such RSM materials differ significantly and their performance remains to be established separately as well as the properties of the construction products produced by them. Besides this each production unit has its own experience with raw materials for its production and introducing a new one is always causing some initial doubts. ISF not only covers preliminary expectations but even exceeds them.

One of the main purposes of this article is to present opportunities to academics, researchers, design engineers, research and development & production managers in companies, specialists and contractors, for sustainable building products development of this not so well-known material with great potential. Most of the presented applications are prepared on industrial scale with different percentages of ISF for testing the effect of its quantity on the properties of the final products.
Alkali-activated geopolymers based on iron-rich slag from copper industry
Authors: Nikolov A
Published: November 2020

In the present study geopolymers were prepared using fayalite slag (iron-silicate fines) from copper producing plant (Aurubis Bulgaria AD). The influence of the different concentrations of alkali activator on properties and structure was examined. The prepared geopolymers were characterized by maximal compressive strength of about 27 MPa. The microstructural examination revealed that only small amount of the precursor reacted, but certain amount of ferric iron (Fe3+) participate in the structure of newly formed geopolymer gel.
Influence of sulphate ions on the crystal chemistry of white cement mortars with a high content of marble filler powder
Authors: Stoyanov V A , Petkova V , Kostova B
Published: November 2020

Objects of this research are white cement mortars, characterized by both of high content of addition of marble powder and reduced water-cement ratio. The hardened cement mortars, formed after 28-and 120-day curing under standard conditions, are studied. The newly formed phases, containing [SO4]2-, [CO3]2-, [OH]-, etc., are identified using X-ray powder diffraction, infrared spectroscopy and thermal analysis (coupled with analysis of the outgoing gas mixture by mass spectrometry). Based on of the formed calcium silicate hydrates, calcium aluminate hydrates, the influence of sulphate ions is analysed and the mechanism of the thermal decomposition reaction at high temperatures in an oxidizing gas environment is studied. This allows us to establish that the hydration of Portland cement depends on the addition of marble powder (technically calcium carbonate CaCO3), as well as mono- and hemicarboaluminates are formed instead of monosulphoaluminates.
Effect of depth of epoxy coated lapped splices on bond efficiency
Authors: Osifala K B
Published: November 2020

This paper gives a report of research investigation carried out to study the effect of depth of epoxy coated lapped spliced bars on bond strength and efficiency. Thirty-six full size beams of varying lengths and sectional dimensions with lap spliced bars in constant moment region were cast and tested in a four-point bending system. Bond strength and efficiency of epoxy coated top reinforcing bars were investigated using beams with 300 mm and 500 mm depths. Three beam sizes (300 × 180 mm, 300 × 200 mm and 300 × 230 mm) and high yield reinforcing bars (16 mm, 20 mm and 28 mm) were coated with epoxy over the lap length and used with each depth. The ultimate moments from the tests were used to determine the stress developed in the reinforcing bars. Coated top reinforcing bars were found to have lower bond strength and efficiency than coated bottom reinforcing bars in the depths investigated. The location factor, α, which is a reduction factor determined using an average of three beams, for epoxy coated top bars were found to be 0.86, 0.84 and 0.89 respectively for 16 mm, 20 mm and 28 mm diameter bars at 300 mm depth and 0.62, 0.80 and 0.86 respectively for 16 mm, 20 mm and 28 mm diameter bars at 500 mm depth.
Progressive Collapse of flat slab structures – key elements and connections
Authors: Sokolova G
Published: November 2020

The loss of even one vertical support member can lead to catastrophic consequences and the progressive collapse of big portion or even the entire structure of the building. This report presents a computational study of a single-story, non-scaled 3D fragment of a high-rise concrete flat slab structure building with peripheral beams along the facade in case of dynamic failure of a column. The main objective is to examine alternative load paths for the transfer of stress from the peripheral beams to the columns, across the slab and its punching areas. In case of accidental failure of an outer column, the facade beams serve as prevention which reduces the redistribution of loads to the interior, ie. to the columns with critical slab punching areas. Research on the performance of peripheral beams and the key role of corner columns is the focus of this report.
Seismic behaviour before and after strengthening of solid confined masonry walls with glass fiber reinforced polymers - analysis of hysteresis curves, obtained by shaking table tests
Authors: Abdulahad E , Mahmud E
Published: November 2020

Masonry is one of the oldest building construction methods used by man thousands of years ago, and one of those used today. The masonry buildings look stable and give a sense of security and comfort, leaving a lasting impression of strength. Shaking table tests are planned in order to deepen the understanding of the behaviour of confined masonry structures. This paper presents the observations from a series of shaking table tests done on a 1:1 scale confined masonry wall model without openings. The specimen was tested under constant gravity load and incrementally increasing in-plane loading seismic up to the occurrence of damage. The horizontal load applied is in-plane of the specimen. Then, the seismically damaged specimen was strengthened, using glass fiber reinforced polymers (GFRPs), and tested again. The specimen was strengthened on the surface of two sides. Hysteresis curves before and after with GFRPs wall strengthening are analysed. The tests results indicate that the GFRP system restores and increases the lateral load capacity of strengthened walls. Moreover, GFRP helps to increase the area of hysteresis curves, leading to increased seismic energy dissipation.
Seismic assessment of consequences in the building stock in Bulgaria based on statistical calibration of public data
Authors: Kaneva A
Published: November 2020

A generally accepted step to reduce the consequences of strong earthquakes and be prepared to face them, is to assess the possible damages and undertake countermeasures proactively. The aassessments are made based on analyses of seismic hazard and vulnerability of building structures. To collect the data about the buildings requires a lot of financial resources and time especially for a large-scale study. In this paper an assessment of the possible consequences in the building stock of a town in Bulgaria is performed by using public data. Some problems arising in the use of the available public data for the building stock in Bulgaria collected by the National Statistical Institute are discussed. A statistical approach is applied to calibrate this data for the buildings to classify them according the building typology and period of construction, which are main factors that determine their vulnerability. The consequences to the building stock has been evaluated with public data for several large cities in Bulgaria. Different approaches for the relation between the earthquake intensity and the level of damage are applied. Comparison of the calculated damages in the building stock of the town of Pernik and the observed damages during the 22 May 2012 earthquake is made. The results are discussed in view of applying public data for the building stock to estimate possible consequences from a strong earthquake in large urban areas.
Main features and issues in the design of tall buildings in Bulgaria
Authors: Traykov A
Published: November 2020

In recent years, construction of tall buildings has been flourishing in many places around the world. In a considerable number of cases it is very much a matter of demonstrating financial and technological capabilities. Bulgaria is not isolated from these processes, mainly designing and building office, residential and hotel buildings with reinforced concrete structures. This requires systematization of information and experience in the design of tall buildings, as well as discussing the basic features and problems in the structural design of tall buildings and making recommendations based on existing experience and trends observed in the development of analysis methods and design. Basic issues related to height, architectural solutions, structural systems and other aspects that affect design solutions and problems related to these issues are discussed. The regulations related to the design of structures of tall buildings were commented on, with the main issues discussed mainly based on structural Eurocodes. The most important aspects of computer modeling of tall building structures and numerical analysis are discussed. Common problems related to the dimensioning and detailing of basic structural elements are commented. Finally, general recommendations are made for the research and design of tall buildings with reinforced concrete construction.
Analysis of the load bearing capacity of scaffoldings used in Poland
Authors: Błazik-Borowa E , Bęc J , Jamińska-Gadomska P , Kawecki B , Lipecki T , Pieńko M , Robak A , Szulej J , Wielgos P
Published: November 2020

The paper presents static-strength analyses of 120 scaffoldings used on construction sites in Poland in the period 2016-2018. The geometry of each analysed scaffolding was taken from measurements made on the construction sites, and the scaffolding loads were determined on the basis of the standards requirements. The results of scaffolding inventory, surveying measurements, measurements of axial forces in standards, and measurements of scaffolding accelerations during vibrations were used to create numerical scaffolding models. For each scaffolding, buckling load analysis and linear static analysis were performed for four load cases which took into account self-weight, parallel and perpendicular wind actions and service load. On the basis of numerical analyses, it was found that 14 scaffoldings could fail due to loss of stability. For 56 scaffoldings, the ultimate limit state condition was not met in at least one group of components, therefore 47% of tested scaffoldings should not be approved.
Smartphone application for structural health monitoring
Authors: Stoilov G , Pashkouleva D , Kavardzhikov V
Published: November 2020

In recent years, smartphone technologies have developed rapidly. They are increasingly taking on the role of laptops and compact personal computers, as well as digital cameras, through which measurements can be taken in various industries including the building industry. This ability to receive, process and transmit measurement data makes them a tool allowing civil engineers to inspect the operational condition of building structures and their constituent parts (so-called “Structural Health Monitoring”). In this paper, a contemporary review of publications related to the use of the smartphone as a measuring tool in structural health monitoring is made. It is seen as an opportunity to develop a “real-time” smartphone application, to measure and visualize fields of displacement and deformation of structural elements. This possibility is based on digital image correlation analysis. The working principles of the smartphone application using the smartphone camera are described and the capabilities of the smartphone application, developed by the authors, for the measurement of two-dimensional fields of displacement and deformation are illustrated.
Analysis of the construction site waste management plans in Bulgaria, adopted in the period 2015-2017
Authors: Stoyanov V A , Petkova V , Andonova V
Published: November 2020

At the end of 2017, a new “Ordinance on construction and demolition waste management and use of recycled building materials” was adopted in Bulgaria without assessing the application of the existing one. Then and until now, there is no reliable public data available on construction and demolition waste, based on which to make a statistical assessment and make management decisions. To clarify the manner of preparation and implementation of construction site waste management plans, a study of existing accepted projects was conducted. They were evaluated based on their content, chosen measures, and recognition of the application of priority order (hierarchy) in the management of the generated construction and demolition waste. Based on the analysis, it is argued that to make the Ordinance on construction and demolition waste management more effective, it should be accompanied by increasing the reliability and quality of waste data, implementing specific management decisions based on knowledge of material flows, development of a market for reused construction products and specialization of the designers of these plans.