bluuebunny/crossref_metadata_2025 huggingface dataset:
PHYSICAL PROPERTIES OF FOAMED CONCRETE INCORPORATING COCONUT FIBRE
Authors: Mydin M. A. Othuman , Md. Noordin N. , Utaberta N. , Mohd Yunos M. Y. , Segeranazan S.
Published: May 2016

Nowadays, the high cost of conventional construction material becomes the dominating factor which affecting the housing system in our country. As an alternative method to overcome this disadvantage which is decreasing the strength of the building, it is important to do research on any alternating materials which will decrease the cost and increase the strength of concrete. This conventional construction material likewise made some problems to nature. But coconut fiber, which is natural fiber, makes no impact on environment furthermore increases the strength of concrete compares to other fiber. This paper focuses on the investigation and experimental analysis on the physical characteristics of lightweight foamed concrete (LFC) incorporating coconut fibers composites with different volume percentage of fibers 0.2 and 0.4. LFC is produced by cement paste or mortar in which air-voids are entrapped in the mortar by the suitable foaming agent. Two densities of LFC, 850 and 1200 kg/m³, were cast and tested. Approximately 0.75% of cement percentage of super plasticizer was used to enhance workability of the fresh mix. The results of the test showed that the both of physical properties of the concrete increases with curing age and quantity of coconut fiber.
MAINTAINABILITY AND DESIGN ASPECT OF PUBLIC HOSPITAL
Authors: Jaafar Mastura , Othman Nur Liyana
Published: May 2016

Maintainability is a pertinent aspect to be considered in building design and is a key approach associated with design and maintenance. Considering maintainability at design stage is important to reduce maintenance and operation costs and ensure that a building can efficiently perform its function. This paper assesses the design impact on maintainability of Hospital Sutanah Bahiyah in Alor Setar. This study analyzes the maintainability from three building aspects (i.e., accessibility, selection of type of material, and environment) based on a secondary report and a focus group interview. Findings support the need of a design team that considers maintainability to help the maintenance team perform maintenance work.
THERMAL CHARACTERISTICS OF EXPERIMENTAL POROUS PAVERS
Authors: Haron Siti Nursa’adah , Abdul Ghani Abdul Naser , Abdul Rahman Abdul Malek
Published: May 2016

Pavement covers quite high percentage of the urban fabric and contributes highly to the development of heat island. This research studies the usage of aggregates and epoxy binder (cement free binder) as the major materials for pervious pavements. Eight samples were produced using different sizes of aggregates by mixing with non-cement epoxy binder pervious pavements. The samples were then tested with thermal performance and infiltration test. The study indicated that the higher void structure in the pavers will cause faster infiltration but contributing to the higher thermal performance. However, the higher surface temperature is expected to promote more evaporation and consequently reduce the overall pavement and surrounding temperature.
THE SIGNIFICANCE OF UNIQUENESS, COMFORT, SECURITY AND SAFETY TO PLACE ATTACHMENT
Authors: Karsono Bambang , Indira Sri Shindi , Deni Deni
Published: May 2016

Uniqueness, comfort, security and safety are attributes in a place that can influence the place attachment. Place attachment is the relationship of function and emotional components between people and place that creates meaning. Place attachment in public open spaces is usually related with the bond of the people and its physical environment and also the perception either negative or positive of the place. This research examine the role of uniqueness, comfort, security and safety as attributes which influenced the place attachment in the Kuching Riverfront Promenade (KRP), a popular public space among the locals people. Mixed method approach was using in this research to discovers the role of attributes to place attachment. A total of 165 respondents and 18 stall operators were interviewed, at the same time field survey was conducted in a selected area of the promenade. Findings indicated that the attributes: uniqueness, comfort, security and safety have a strong impact to respondents to identify the local environment and it exerts influence on the place attachment.
STRUCTURAL PERFORMANCE OF OIL PALM SHELL LIGHTWEIGHT AGGREGATE CONCRETE WALL PANEL ON INSULATION CONCRETE CAPACITY
Authors: Serri Eravan , Suleiman Mohd Zailan , Talib Roslan , Jabar Khairul Azmi
Published: May 2016

This paper presents of an investigation conducted the structural performance of oil palm shell lightweight aggregate concrete (OPSLAC) wall panel. Load-deflection characteristic on OPSLAC wall panel was conducted. Further, the effect of Stress-strain relationship and buckling effect on compression load was investigated. The variable selected are size of oil palm shell (OPS). Three wall panel specimens were prepared, and tests on compression load were conducted. The load-deflection result showed the changing on OPS shape used. The convex of OPS influence the bond within aggregate and cement paste. Further, the increasing of compression load is related to the formation and growth of micro cracks. As ultimate strength is approached, increased load and bulk paste micro cracks join to form continuous cracks parallel to the direction of loading on stress-stain curve. After 70% from the ultimate loading, the extent of cracking is so great that OPSLC cannot support additional load.
GREEN CONCRETE MADE OF OYSTER SHELL WASTE TO SUPPORT GREEN BUILDING MATERIAL
Authors: Erni S. , Gagoek H. , Purwanto K.
Published: May 2016

Oyster shells in this research have function as both cement and fine aggregate substitution as well as provide aesthetic value on concrete materials. Types of shells observed in this research are: green mussels (Perna viridis. Linn), blood clams (Anadara granosa Linn) and scallops (Placuna placenta Linn). This paper compares performances of concrete materials made of three oyster shells on density, compressive strength and acoustical aspects consisting Sound Transmission Loss (STL) and Absorption Coefficient (Î±). Green material made of Anadara granosa Linn shell has the greatest compressive strength with the value of 200 kg/cm2. The acoustical tests show that the three materials have a range of STL between 6.3931 and 7.953 dB, while the greatest absorption coefficient is material made of Perna viridis shell with value of 0,05.Â
BARRIER OF VENTILATION MODES TO ACHIEVE A BALANCE ENVIRONMENT IN REFURBISHED PRESCHOOLS
Authors: Muhamad Salleh Naziah , Esa Muneera , Kamaruzzaman Syahrul Nizam , Mahyuddin Norhayati , Muhammad Darus Fairus
Published: May 2016

The preschool education is compulsory to children in Malaysia. This regulation has encouraged more premises to be refurbished as a preschool building. This paper examines the pupilsâ€™ absenteeism and the prevalence of Sick Building Symptoms (SBS) initiated in congested private preschool with different ventilation. The study analysed data from the attendance record of 10 classrooms and the questionnaire surveys administered to 151 parents about their children health symptoms once they were leaving the schools building. Indoor Carbon Dioxide (CO2) measured as indicator of the problems. Questions on SBS used 5-point likert scale with symptoms concern on nose, eye, head, throat, skin, breath and tiredness. The descriptive and chi-square test applied to obtain the association of SBS and ventilation strategies in the classrooms. With quantitative and qualitative explanation, the unhealthy environment in refurbished pre-schools explained respiratory symptoms and higher rates of absenteeism frequently reported in air-conditioning (AC) classrooms due to concentrations of CO2 exceeded 1000 ppm. These symptoms show there were weaknesses in ventilation performance and environment in the selected preschools. Further analyses on objective measurements in future research are strongly recommended.
HYGROTHERMAL PERFORMANCE OF BUILDING ENVELOPES IN THE TROPICS UNDER OPERATIVE CONDITIONS: CONDENSATION AND MOULD GROWTH RISK APPRAISAL
Authors: Ali Maisarah , Olaide Oladokun Majeed , Osman Samsul Bahrin , Mohd Din Shamzani Affendy , Ibrahim Mohd Sharifuddin , Yusof Faridah
Published: May 2016

Poor indoor hygrothermal performance increases the risk of indoor moisture problems and deterioration due to mould growth, corrosion and damage to archival materials. Hence, proper control of indoor thermohygric intensity abates indoor moisture and its associated problems. This paper presents the results of envelopes hygrothermal performance assessments in a hot and humid climate building with varying operational profile between adjacent spaces. The case-studied building runs on 24hrs cooling mode in one part against natural and/or mechanical supply-exhaust fan means on the other. In-situ experiments were combined with hygrothermal analytical methods to assess the envelope thermal quality together with the operative conditions against condensation and mould growth risks. The results show that the building is overcooled leading to poor envelope hygrothermal performance with associated condensation and mould growth problems on non-air-conditioned sides of the envelopes.Â
THERMAL EFFECTS OF PRENATAL ULTRASOUND EXPOSURE ON PARATHYROID HORMONE SECRETION OF ORYCTOLAGUS CUNICULUS AND THEIR CORRELATION WITH SERUM BIOCHEMICAL REACTIONS AND BONE VOLUME
Authors: Iza Nurzawani C. I. , Sulaiman M.
Published: May 2016

Calcium is the most essential element to provide energy to the body system and PTH secretion is responsible for the calcium regulations. PTH imbalance can cause serious medical conditions. Heat is one of the factors that is able to cause disturbance in the PTH secretion. As ultrasound has the potential to produce heat, its imprudent use during pregnancy may cause disturbance in the formation of the parathyroid gland. This study was done using young-aged oryctolagus cuniculus to evaluate PTH secretion and its correlation with the biochemical reaction and bone volume. New Zealand White rabbits were time-mated and exposed to 30, 60 and 90 minutes of prenatal ultrasound at 1st, 2nd and 3rd stage of gestation accordingly. The control group was left for full term delivery without receive ultrasound exposure. In 1 month-aged subject, the lowest PTH level which significantly different from the control was noted after exposed prenatally in the 1st stage for 90min (3.56Â±0.75). Meanwhile, in the 5 months-aged subject, the lowest PTH level was noted in the 3rd stage group after 90min of exposure (2.98Â±0.62). The reduction in PTH was found to affect the biochemical reactions, but not the bone volume. Â Â
MANUFACTURE OF ACOUSTICAL ONE SIDE-WAFFLE PANEL MADE OF NATURAL RESOURCES WITH HYDRAULIC HOT PRESS MACHINE
Authors: Setyowati E. , Satyapratama A. , Atmadja S. T. , Hardiman G.
Published: May 2016

Waste generated from natural resources should be recycled as more useful materials. This research has produced acoustical waffle panel material which is useful as an absorber on the noisy housing. Acoustical waffle panels was made by Hydraulic Hot Press machine. The purpose of this discussion is to describe the machine design process and compare waffle panels made of coconut fiber and wood sawdust in the best acoustic performances. The result is that the hydraulic hot press machine has the structural strength and stability on the load of 2,500 N and 5,000 N. The hot press machine is safe for both the transverse tensile stress and longitudinal tensile stress which are smaller than the allowable stress of steel material of 40 at 1,100 kg/cm2. It also has the highest Sound Transmission Loss (STL) with the value of 40. 059 dB.
IMAGE RECONSTRUCTION BASED ON COMPRESSIVE SAMPLING USING IRLS AND OMP ALGORITHM
Authors: Dyah Irawati Indrarini , B. Suksmono Andriyan
Published: May 2016

We proposed compressive sensing to reduce the sampling rate of the image and improve the accuracy of image reconstruction. Compressive sensing requires that the representation of the image is sparse on a certain basis. We use wavelet transformation to provide sparsity matrix basis. Meanwhile, to get a projection matrix using a random orthonormal process. The algorithm used to reconstruct the image is orthogonal matching pursuit (OMP) and Iteratively Reweighted Least Squares (IRLS). The test result indicates that a high quality image is obtained along with the number of coefficients M. IRLS has a good performance on PSNR than OMP while OMP takes the least time for reconstruction.
IMMERSIVE BICYCLE GAME FOR HEALTH VIRTUAL TOUR OF UIN MAULANA MALIK IBRAHIM MALANG
Authors: Faisal Muhammad , Nurhayati Hani , M. Arif Yunifa , Kurniawan Fahrul , Nugroho Fressy
Published: May 2016

Cancer is the leading cause of death in the world. More than 10 million people worldwide The goal of this research is to promote UIN Maliki Malang using immersive tools bicycle for human health. The system developed using combination of bicycle and computer with various sensors on the wheels, steering and brakes. The device consists of a mountain bike in front of the monitor are useful to display virtual Tour. Childrenâ€™s reactions to the virtual peer indicate that their virtual peer framework is a promising platform for future behavioral studies of peer influences on childrenâ€™s bicycle riding behavior.Â  The system results shows immersive bicycle road in UIN Maliki Malang area. This system is useful for refreshing and relaxing human body.
PHYLOGENETIC ANALYSIS OF LOCAL ENDEMIC BUFFALO (BUBALUS BUBALIS) BASED ON CYTOCHROME B GENE IN CENTRAL INDONESIA
Authors: Amin M. , Suarsini E. , Azmi I. , Gofur A.
Published: May 2016

Buffalo population in the central of Indonesia such as Bali, NTB, and Sulawesi is decreased. Cause of the decline of buffalo population is inbreeding. For conservation efforts to avoid inbreeding required the identification of buffalo genetic variations on molecular scale as phylogeny analysis with cyt b gene. The purpose of this study were to reconstruct the phylogenetic tree of buffalo ((Bubalus bubalis) in the central of Indonesia with cyt b gene. Animal materials were collected from four different area: Bali, Lombok, Bima and Toraja. DNA isolation, PCR (polymerase chain reaction) was conducted under standar protocols. Sequence from four representaive animals based on area were used to contruct the phylogenetic tree and haplotype network. Analyses of plylogenetic tree showed that the reconstruction has one major clade and two sub clade. It showed that buffalo in central of Indonesia had close genetic relationship.
POTENTIAL OF NATURAL AND SYNTHETIC FIBRES ON FLEXURAL PERFORMANCE OF FOAMCRETE MORTAR
Authors: Mydin Md Azree Othuman
Published: May 2016

This research investigates the potential of natural and synthetic fibres on flexural strength of foamcrete mortar. The are 7 different types of fibres had been used such as pulverized fuel ash, wood ash, silica fume, palm oil fuel ash, polypropylene fibre, coconut fibre and steel fibre. These natural and synthetic additives have different abilities that contribute positive outcomes to the properties of foamcrete mortar. Pozzolanic materials and fibres were used as additives to be included with control foamcrete mortar mixtures in order to enhance its flexural properties. From the overall analysis, it has been confirmed that coir fibre recorded the highest flexural strength in 7 days compared to other additives and the control sample. Coir fibre of 0.4% reached highest strength in 180 days without allowing other additives to overcome its overall flexural strength. It should be pointed out that, the more the addition of fibres in the base mix, the higher the strength obtained due to its low cellulose content.
RISK VARIABLE ON CONTRACTOR’S TENDER FIGURE IN MALAYSIA
Authors: Saaidin Sabihah , Endut Intan Rohani , Abu Samah Siti Akmar , Mohd Ridzuan Ahmad Ruslan , Abd Razak Nur Nabihah
Published: May 2016

Construction industry like other industries is subject to risks due to the unique and complexity of the construction industries. It shows the risk exposure at highest level during the tendering process. The objective of this paper is to evaluate risk variable on contractor’s tender figure in Malaysia. To achieve the objective, questionnaire survey was conducted on G7 contractor in Malaysia. A total of 120 usable postal questionnaires was received. The findings have shown quality expectation, price inflation of construction materials, the risk involved in the project and financial capability of the client are most significant factors to be considered by contractors when estimating the pricing risks. The study recommended that competent contractors should be allowed to tender project as to see the risk variable inherent during tendering process that will affect project performance.
RESISTANCE OF BUILT-UP COLD-FORMED STEEL CHANNEL COLUMNS FILLED WITH CONCRETE
Authors: Mohd Sani Mohd Syahrul Hisyam , Muftah Fadhluhartini , Muda Mohd Fakri , Siang Tan Cher
Published: May 2016

Cold-formed steel (CFS) channel infilled with concrete could increase its ability and stiffness by avoiding failure due to local buckling. Besides, the built-up bolted CFS channel column could serve as permanent formwork, decreased waste material and yet increase economical construction. This study aims to investigate the strength of built-up CFS channel columns infilled with concrete. Two CFS channel sections are situated face to face, connected and strengthen by using M10 bolts and nuts. Then, the 900 mm built-up column is filled with normal concrete of grade C30. Six samples with different end and central bolt spacing were tested. Material properties of CFS and concrete, and the mechanical properties of bolts are also investigated. From the result, the column with concrete on shortest end bolt spacing gave highest ultimate load and reported 68 – 78 % different when compared to similar column without concrete infilled. The failure mode of the column is global buckling and supports yielding, and the concrete is failed due to cracking and breaking. Equation of the relationship between bolt spacing either at the end or central and ultimate load is established.
ENHANCING LANDFILL GAS RECOVERY- A REVIEW
Authors: Olisa Emmanuel , Sapari Nasiman , Malakahmad Amirhossein , Henry Ezechi Ezerie , Riahi Ali
Published: May 2016

Although landfills serve as an easy and very economic means for disposing wastes, it poses threat to the environment as it generates both leachate and greenhouse gases, including methane (CH4) and carbon dioxide (CO2). Nowadays, landfills are equipped with gas recovery components thereby making it possible for more methane gas to be collected and used as an alternative source of green energy. Currently, various technologies have been employed in managing landfill sites in order to attenuate environmental degradation; Revegetation technologies, methane oxidation, anaerobic digestion, waste washing and pre-treatment are some of the methods currently used. This review presents an overview of the technologies and methods employed for enhancing landfill gas mitigation and recovery.
REQUIREMENTS ANALYSIS OF GEOTHERMAL ENERGY-BASED COLD STORAGE: CASE STUDY IN INDONESIA
Authors: Kumashiro Hiroki , Tjhi Mikhael , Yudoko Gatot , Dowaki Kiyoshi
Published: May 2016

This article presents the results from a viability analysis of geothermal energy-based cold storage for food supply chains inIndonesia. In this study, it was assumed that middlemen used cold storage as part of the supply chain. Gatekeepers were chosen based on three criteria: place, people, and prospect; and the gatekeepers, thus chosen from different societal groups, were then interviewed to validate outsiders’ assumptions. Finally, results were categorized into four interest classifications: technical, economic, environmental, and social.
BEHAVIOUR OF ECCENTRICALLY LOADED SLENDER CONCRETE FILLED STEEL TUBES COLUMNS
Authors: Petrus Clotilda , Abd Hamid Hanizah , Ibrahim Azmi , Nyuin Joe Davylyn
Published: May 2016

This paper presents an experimental investigation into the structural behaviour of eccentrically loaded concrete filled, thin walled, steel tubular slender column with tab stiffeners (CFST). The primary parameters studied through the experimental work are load eccentricity and type of stiffeners. Three different types of stiffeners used in this study are longitudinal stiffeners of 10mm height, longitudinal and tab stiffeners of 25mm height and longitudinal and extended tab stiffeners at 40mm. The effects of the stiffeners on the structural behavior were investigated experimentally using 26 specimens of slender CFST, loaded with eccentricity ranging from 0 mm to 60 mm. It was observed that all specimens failed mainly by overall buckling and, the compressive strength and bending strength of the specimens decreases as the applied load eccentricity increases.
EXPERIMENTAL AND NUMERICAL ANALYSIS OF INTERACTION BETWEEN SUBSOIL AND POST-ENSIONED SLAB-ON-GROUND
Authors: Mynarcik Petr , Labudkova Jana , Koktan Jiri
Published: May 2016

The paper presents the process of a static load test on post-tensioned concrete industrial floor model in the first part and a numerical model of this task in the second part. The experimental model was designed as a cutout of a post-tensioned concrete industrial floor and the static load test was conceived as a simulation by loading the base plate of a heavy rack. The described static load test was part of a series of experiments focused on the problematics of interaction between concrete structures and subsoil and was realized at the Faculty of Civil Engineering, VŠB –Technical University of Ostrava.
ABOVEGROUND BIOMASS AND CARBON STOCK ESTIMATION USING DOUBLE SAMPLING APPROACH AND REMOTELY-SENSED DATA
Authors: Mohd Zaki Nurul Ain , Abd Latif Zulkiflee , Zainal Mohd Zainee
Published: May 2016

Tropical forest embraces a large stock of carbon and contributes to the enormous amount of aboveground biomass (AGB) in the global carbon cycle. In order to quantify the carbon inventory, field data is vital for accurately determining the forest parameter such as diameter at the breast height (DBH), height  of the tree (h) ,crown diameter (CD) and tree species. The merging of the multi-sensory remote sensing which is LiDAR (Light Detection and Ranging) and very high resolution satellite imagery can reduce the labor intensive of field sampling for a large area of carbon inventory data. Double sampling approach which is combination of the field sampling plot measurement with ancillary remote sensing data used to improve the precision of AGB estimation compared by using field data alone. Hence, this study aims: (1) to describe the use of field data plots in a statistical way, and (2) to determine the potential of LiDAR data in a double sampling forest aboveground biomass and carbon stock inventories and (3) to compare the used of field data plot itself or combination with LiDAR data to quantify the aboveground biomass and carbon stock for upcoming inventories.
DIMENSIONAL ANALYSIS RELATIONSHIPS OF STREAMBANK EROSION RATES
Authors: Saadon Azlinda , Ariffin Junaidah , Abdullah Jazuri , Mat Daud Norhidayati
Published: May 2016

Bank erosion is commonly associated with river meandering initiation and development, through width adjustment and planform evolution. It consists of two types of erosion processes; basal erosion due to fluvial hydraulic force and bank failure under the influence of gravity. Most of the studies only focused on one factor rather than integrating both factors. Evidences of previous works have shown integration between both processes of fluvial hydraulic force and bank failure. Bank failure seldom treated as a probabilistic phenomenon without assessing the physical characteristics and the geotechnical aspects of the bank. Thus, the objective of this paper is to investigate factors governing streambank erosion process and to perform a dimensional analysis considering the physical characteristics of both processes namely fluvial erosion and mass failure and their interaction.
CORROSION PROCESSES ON WEATHERING STEEL RAILWAY BRIDGE IN PRAGUE
Authors: Urban Viktor , Krivy Vit , Buchta Vojtech
Published: May 2016

This contribution deals with experimental corrosion tests carried out on the weathering steel railway bridge in Prague. The basic specific property of the weathering steel is an ability to create in favourable environment a protective patina layer on its surface. Since 1968 weathering steel is used under the name “Atmofix” in the Czech Republic and can be used as a standard structural material without any corrosion protection. The weathering steel Atmofix is mostly used for bridge structures and lattice transmission towers. Some of these constructions built in the Czech Republic have been assessed and inspected in the last few years. Authors of this paper developed a new methodology of non-destructive experimental testing of corrosion processes. Testing specimens are installed on typical surfaces of steel bridges in such a way to simulate real conditions of the examined surface. This paper describes results of corrosion tests (thickness of corrosion products, corrosion losses and X-Ray analysis) after one-year exposure, correlation factor and dependence of location.
INDUCTION, MULTIPLICATION, AND ACCLIMATIZATION OF RED BETEL PLANT (PIPER CROCATUM RUIZ AND PAV.) BY IN VITRO ORGANOGENESIS
Authors: Sianipar Nesti Fronika , Verlina Verlina , Rosaria Rosaria
Published: May 2016

Red betel is an herbal plant with anticancer activities. Propagation of red betel by conventional vegetative method has low multiplication factors. The purpose of this research was to increase the propagation rate of red betel by utilizing in vitro culture organogenesis method which was consisted of stages as follows: shoots initiation, shoots multiplication, root induction, and acclimatization. Shoots induction from axillary bud was achieved on MS 3 mgL-1 BAP media. Shoots were multiplicated on MS (0, 0.5, 1, 1.5 mgL-1) BAP, (0.01, 0.03, 0.1, 0.3 mgL-1) TDZ, and (0.01, 0.03, 0.05, 0 mgL-1) TDZ combined with 0.5 mgL-1 NAA. Roots were induced on MS (0, 0.5, 1, 1, 5 mgL-1) NAA. The maximum number of shoots (4.4 ± 0.9) was achieved on MS 1 mgL-1 BAP. The maximum number of roots (22.8 ±9.7) was achieved on MS 0.5 mgL-1 NAA. The highest survival rates of red betel plants during acclimatization and post-acclimatization periods were 88% and 100%, respectively. Red betel had been successfully multiplicated by in vitro direct organogenesis.
COMPARISON OF VSM, GVSM, AND LSI IN INFORMATION RETRIEVAL FOR INDONESIAN TEXT
Authors: Pardede Jasman , Husada Milda Gustiana
Published: May 2016

Vector space model (VSM) is an Information Retrieval (IR) system model that represents query and documents as n-dimension vector. GVSM is an expansion from VSM that represents the documents base on similarity value between query and minterm vector space of documents collection. Minterm vector is defined by the term in query. Therefore, in retrieving a document can be done base on word meaning inside the query. On the contrary, a document can consist the same information semantically. LSI is a method implemented in IR system to retrieve document base on overall meaning of users’ query input from a document, not based on each word translation. LSI uses a matrix algebra technique namely Singular Value Decomposition (SVD). This study discusses the performance of VSM, GVSM and LSI that are implemented on IR to retrieve Indonesian sentences document of .pdf, .doc and .docx extension type files, by using Nazief and Adriani stemming algorithm. Each method implemented either by thread or no-thread. Thread is implemented in preprocessing process in reading each document from document collection and stemming process either for query or documents. The quality of information retrieval performance is evaluated based-on time response, values of recall, precision, and F-measure were measured. The results show that for each method, the fastest execution time is .docx extension type file followed by .doc and .pdf. For the same document collection, the results show that time response for LSI is more faster, followed by GVSM then VSM. The average of recall value for VSM, GVSM and LSI are 82.86 %, 89.68 % and 84.93 % respectively. The average of precision value for VSM, GVSM and LSI are 64.08 %, 67.51 % and 62.08 % respectively. The average of F-measure value for VSM, GVSM and LSI are 71.95 %, 76.63 % and 71.02 % respectively. Implementation of multithread for preprocessing for VSM, GVSM, and LSI can increase average time response required is about 30.422%, 26.282%, and 31.821% respectively.
Pneumatic Variable Series Elastic Actuator
Authors: Zheng Hao , Wu Molei , Shen Xiangrong
Published: May 2016

Inspired by human motor control theory, stiffness control is highly effective in manipulation and human-interactive tasks. The implementation of stiffness control in robotic systems, however, has largely been limited to closed-loop control, and suffers from multiple issues such as limited frequency range, potential instability, and lack of contribution to energy efficiency. Variable-stiffness actuator represents a better solution, but the current designs are complex, heavy, and bulky. The approach in this paper seeks to address these issues by using pneumatic actuator as a variable series elastic actuator (VSEA), leveraging the compressibility of the working fluid. In this work, a pneumatic actuator is modeled as an elastic element with controllable stiffness and equilibrium point, both of which are functions of air masses in the two chambers. As such, for the implementation of stiffness control in a robotic system, the desired stiffness/equilibrium point can be converted to the desired chamber air masses, and a predictive pressure control approach is developed to control the timing of valve switching to obtain the desired air mass while minimizing control action. Experimental results showed that the new approach in this paper requires less expensive hardware (on–off valve instead of proportional valve), causes less control action in implementation, and provides good control performance by leveraging the inherent dynamics of the actuator.
Mechanical Efficiency of Hydraulic Air Compressors
Authors: Pavese Valeria , Millar Dean , Verda Vittorio
Published: May 2016

After air and water mixing, the process of gas compression in the downcomer shaft or pipe of a hydraulic air compressor is considered nearly isothermal due to (i) the mass flow rate of water being typically of three orders higher than that of the gas it compresses, (ii) water having a heat capacity approximately four times that of air, and (iii) the intimate contact and large heat transfer area between the gas phase and the liquid phase of the bubbly flow. A formulation for estimation of the efficiency of a closed- or open-loop hydraulic air compressor, expressed in terms of the principal hydraulic air compressor design variables, is presented. The influence of a hitherto underappreciated factor affecting the performance of these installations, such as the solubility of the gas being compressed in the water, is explored. A procedure for estimating the yield of compressed gas, accounting for these solubility losses, is explained and used to determine the mechanical efficiency of historical hydraulic air compressor installations from reported performance data. The result is a significant downward revision of hydraulic air compressor efficiency by approximately 20% points in comparison to most reported efficiencies. However, through manipulation of cosolute concentrations in the water, and the temperature of the water (through regulation of the ejection of compression heat), the mechanical efficiency can be increased to the formerly reported levels. The thermo-economic implication of these efficiency determinations is that in a modern context, hydraulic air compressors may be able to outperform conventional mechanical gas compression equipment.
Assessment and Evolutionary Based Multi-Objective Optimization of a Novel Renewable-Based Polygeneration Energy System
Authors: El-Emam Rami S. , Dincer Ibrahim
Published: May 2016

In this paper, a renewable-based integrated energy system is developed, analyzed, and optimized to achieve better performance. The present system is designed to be driven by concentrated solar thermal and biomass energies. Biomass fuel is used as the backup source of energy when the solar energy is not available. The system is designed to produce electricity, cooling, and hydrogen. The power output of the system is provided by solar-driven regenerative helium gas turbine during day time and from biomass gasification driven solid oxide fuel cell (SOFC) unit at night time. The fuel cell stack number is estimated as to provide the same net power. The system operates at energy and exergy efficiencies of 39.99% and 27.47%, respectively, at the optimal point selected based on the optimization analysis. The parametric studies on performance and environmental impact assessment are performed to investigate the effects of several operating parameters on the system performance.
On Relationship Between Time-Domain and Frequency-Domain Disturbance Observers and Its Applications
Authors: Su Jinya , Chen Wen-Hua , Yang Jun
Published: May 2016

This paper provides a generic analysis of the relationship between time- and frequency-domain disturbance observer (DOB) design methodology. It is discovered that the traditional frequency-domain DOBs using a low-pass filter with unity gain can only handle disturbances satisfying matching condition, while the traditional time-domain DOBs always generate an observer with a high-order. A functional disturbance observer (FDOB) is proposed to improve the existing results together with its design guideline, frequency analysis, and existence condition. Compared with the existing frequency-domain DOBs, the proposed FDOB can handle more classes of disturbances, while compared with the existing time-domain DOBs, the proposed FDOB can generate an observer with a lower-order. Numerical examples are presented to illustrate the main findings of this paper including a rotary mechanical system of nonminimum phase.
Computational and Experimental Assessment of Turbulence Stimulation on Flow Induced Motion of a Circular Cylinder
Authors: Kemal Kinaci Omer , Lakka Sami , Sun Hai , Fassezke Ethan , Bernitsas Michael M.
Published: May 2016

Vortex-induced vibrations (VIVs) are highly nonlinear and it is hard to approach the problem analytically or computationally. Experimental investigation is therefore essential to address the problem and reveal some physical aspects of VIV. Although computational fluid dynamics (CFDs) offers powerful methods to generate solutions, it cannot replace experiments as yet. When used as a supplement to experiments, however, CFD can be an invaluable tool to explore some underlying issues associated with such complicated flows that could otherwise be impossible or very expensive to visualize or measure experimentally. In this paper, VIVs and galloping of a cylinder with selectively distributed surface roughness—termed passive turbulence control (PTC)—are investigated experimentally and computationally. The computational approach is first validated with benchmark experiments on smooth cylinders available in the literature. Then, experiments conducted in the Marine Renewable Energy Laboratory (MRELab) of the University of Michigan are replicated computationally to visualize the flow and understand the effects of thickness and width of roughness strips placed selectively on the cylinder. The major outcomes of this work are: (a) Thicker PTC initiates earlier galloping but wider PTC does not have a major impact on the response of the cylinder and (b) The amplitude response is restricted in VIV due to the dead fluid zone attached to the cylinder, which is not observed in galloping.
AntiWear Effect of Mo and W Nanoparticles as Additives for Multialkylated Cyclopentanes Oil in Vacuum
Authors: Zhang Songwei , Li Yi , Hu Litian , Feng Dapeng , Wang Haizhong
Published: May 2016

This work examined friction-reducing and antiwear behaviors of multialkylated cyclopentanes (MACs) oil with Mo and W nanoparticles as additives under vacuum condition (∼10−4 Pa). The tribological evaluation was conducted on a vacuum four-ball tribometer. The results suggested that the MACs oil exhibited the transient high friction in vacuum, resulted into severe adhesive wear to the steel friction pairs. The Mo and W nano-additives could effectively eliminate the severe adhesive wear. When added with Mo nanoparticles, the lubricating life of MACs oil could be prolonged due to the retarded decomposition of MACs, which should be ascribed to the formation of Mo metallic boundary films on steel ball surfaces that was confirmed by the surface analysis. As for W nanoparticle additives, the rolling effect as nano-bearings and the abrasive wear of larger particles due to the aggregation of W nanoparticles are the dual tribological mechanisms.
Damage Identification of Beams Using a Continuously Scanning Laser Doppler Vibrometer System
Authors: Chen Da-Ming , Xu Y. F. , Zhu W. D.
Published: May 2016

A continuously scanning laser Doppler vibrometer (CSLDV) system is capable of rapidly obtaining spatially dense operating deflection shapes (ODSs) by continuously sweeping a laser spot from the system over a structure surface. This paper presents a new damage identification methodology for beams that uses their ODSs under sinusoidal excitation obtained by a CSLDV system, where baseline information of associated undamaged beams is not needed. A curvature damage index (CDI) is proposed to identify damage near a region with high values of the CDI at an excitation frequency. The CDI uses the difference between curvatures of ODSs (CODSs) associated with ODSs that are obtained by two different CSLDV measurement methods, i.e., demodulation and polynomial methods; the former provides rapid and spatially dense ODSs of beams, and the latter provides ODSs that can be considered as those of associated undamaged beams. Phase variables are introduced to the two methods for damage identification purposes. Effects of the order in the polynomial method on qualities of ODSs and CODSs are investigated. A convergence index and a criterion are proposed to determine a proper order in the polynomial method. Effects of scan and sampling frequencies of a CSLDV system on qualities of ODSs and CODSs from the two measurement methods are investigated. The proposed damage identification methodology was experimentally validated on a beam with damage in the form of machined thickness reduction. The damage and its region were successfully identified in neighborhoods of prominent peaks of CDIs at different excitation frequencies.
Suppression of Lateral and Torsional Stick–Slip Vibrations of Drillstrings With Impact and Torsional Dampers
Authors: Hu Lingnan , Palazzolo Alan , Karkoub Mansour
Published: May 2016

Violent drillstring vibrations in a well should be suppressed to prevent premature failure of the drillstring parts and borehole wall and enhance the drilling process. This paper presents novel centralized impact dampers and torsional vibration dampers for lateral and torsional stick–slip vibration suppression which will function well in the harsh environment in the well due to their all-metal construction. A drillstring vibration model is used in this paper to simulate coupled lateral and torsional vibrations of the drillstring with impact and torsional dampers installed in the drill collar (DC). The high-fidelity model utilizes Timoshenko beam finite elements (FEs) and includes stress-stiffening effects to account for the gravity and axial loading effect on the transverse string stiffness. The rotational motions of the impactors result from dry friction tangential contact forces that occur when they contact the DC or sub. The tangential forces utilize a nonlinear Hertzian contact restoring force and a nonlinear, viscous contact damping force, in place of the typical coefficient of restitution (COR) model that cannot provide the required normal and tangential contact forces. The primary conclusions drawn from the simulation results are: (1) both the lateral vibration of the drillstring that is close to the bending critical speeds and the vibration induced by destabilizing forces can be suppressed by impact dampers and (2) the torsional stick–slip motion of the drillstring can be mitigated by the torsional damper.
Appendicular mucinous adenocarcinoma associated with pseudomyxoma peritonei, a rare and difficult imaging diagnosis.
Authors: Chira Romeo Ioan , Nistor-Ciurba Codrut Cosmin , Mociran Andreea , Mircea Petru Adrian
Published: May 2016

Pseudomyxoma peritonei (PMP) is a rare disease, caused by primary mucinous tumors that arise most frequently from appendix, ovary, or pancreas. Usually diagnosis is made by computed tomography, but ultrasonography can be a very useful imagistic method, if this diagnosis is taken into account by the observer. We present a case of a PMP caused by an appendiceal mucinous carcinoma, in a 34-year-old male patient, with family history of malignancies, diagnosed in our department. He was thereafter surgically treated - appendiceal resection, peritoneal lavage - followed by chemotherapy. We underline the importance of ultrasonography, even though at first encounter, the diagnosis of PMP being generally difficult.
The prediction of myometrial infiltration by three-dimensional ultrasonography in patients with endometrial carcinoma: a validation study from Ege University Hospital.
Authors: Ergenoglu Mete , Akman Levent , Terek Mustafa Cosan , Sanhal Cem Yasar , Yeniel Ozgur , Cilengiroglu Ozgul Vupa , Ozsaran Ahmet Aydin , Dikmen Yilmaz , Zekioglu Osman
Published: May 2016

Aim: To predict the myometrial invasion with three-dimensional (3D) ultrasonography in a cohort of patients with endometrial carcinoma by a previously described technique. Material and methods: The moyometrial infiltration was evaluated by 3D ultrasonography before surgery in 54 patients with endometrial carcinoma. After scanning the whole uterus by ultrasonography, three perpendicular planes were identified to find the shortest myometrial tumor-free distance to serosa (TDS) by examining the lateral, anterior, posterior, and fundal parts of the myometrium. Myometrial infiltration was also estimated by the subjective impression of the examiner. The reference standards consist of myometrial infiltration and TDS which are measured by an experienced pathologist. Results: Forty-five patients (age range 45-86 years) were included for the final analysis. Myometrial invasion was ˂50% in 36 and ≥50% in 9 cases at histologic sections. The TDS which is measured with 3D ultrasonography was positively correlated with histologically measured TDS (r=0.474, p=0.001). The best cut-off value for ultrasonographically measured TDS was 9 mm with a sensitivity of 89%, specifity of 61%, positive predictive value of 36%, and negative predictive value of 96%. Subjective impression has a sensitivity of 100%, specifity of 88%, positive predictive value of 69%, and negative predictive value of 100%. Cervical involvement was correctly identified in all 6 cases by subjective impression. Conclusion: This validation study confirms the 3D ultrasonography as a valuable tool for the evaluation of myometrial infiltration in patients with endometrial carcinoma.
The role of lymph node ultrasound evaluation in melanoma – review of the literature.
Authors: Ungureanu Loredana , Jid Carolina Botar , Candrea Elisabeta , Cosgarea Rodica , Șenilă Simona Corina
Published: May 2016

Melanoma is an aggressive tumour, resistant to treatment, derived from melanocytes, with an increasing incidence in the last years in the majority of countries. The most important prognostic factor in the initial stages (I/II) is the presence of metastases at the level of lymph nodes. Ultrasound (US) is a non-invasive method, used in the pre- and post-operative node evaluation due to its high availability, the reduced cost and easy reproducibility. TheUSaccuracy is however dependent on operator expertise. The present article proposes a presentation of the US role in the evaluation of lymph nodes in melanoma patients.
Successful management of a second trimester cesarean scar pregnancy using local methotrexate injection.
Authors: Cheung Vincent Y.T. , Lo Tsz-kin
Published: May 2016

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Portal vein thrombosis in liver cirrhosis – the added value of contrast enhanced ultrasonography.
Authors: Danilă Mirela , Sporea Ioan , Popescu Alina , Șirli Roxana
Published: May 2016

Portal vein thrombosis (PVT) is a frequent complication of liver cirrhosis and its prevalence increases with the severity of liver disease. Patients with liver cirrhosis and hepatocellular carcinoma may have either malignant or blunt (benign) PVT. In these patients, the diagnosis and characterization of PVT is important for the prognosis and further treatment.Ultrasound (US) is the modality of choice for the diagnosis of PVT. The features of PVT on B-mode (gray-scale) US include: dilatation of the portal vein, visualization of the thrombus and, in chronic PVT- cavernous transformation. Sensitivity of US in the diagnosis of PVT is improved by the use of Doppler US and of ultrasound contrast agents. In the latter years, contrast enhanced ultrasound (CEUS) showed high sensitivity in the differential diagnosis between benign and malignant PVT and could be the diagnostic method of choice for the characterization of PVT. Blunt thrombi are avascular and will not enhance during CEUS examination, while a hyperenhancement pattern of the portal thrombus in the arterial phase, with “wash out” in the portal or late phase is typical for malignant PVT.
Coronary sinus fow measured by pulsed Doppler ultrasound is a powerful indicator of coronary blood supply – a pig heart in vitro study.
Authors: Zheng Xiao-Zhi , Wu Jing , Hua Jie
Published: May 2016

Aims: To evaluate the correlation between the coronary sinus fow and the infusion volume in the coronaries and assess the performance of coronary sinus fow in predicting coronary artery occlusion in an isolated pig heart. Material and methods: The coronary sinus fow was measured in 16 isolated pig hearts by pulsed Doppler ultrasound. The correlation between the coronary sinus fow and the infusion volume in different coronary artery was analyzed, and the performance of coronary sinus fow in predicting different coronary artery occlusion was deducted. Results: There were no statistically signifcant differences between the coronary sinus fow and the infusion volume in different coronary artery (p>0.05). The correlations between the coronary sinus fow and the infusion volume in left anterior descending coronary artery (LAD), left circumfex coronary artery (LCX), LAD and LCX, and LAD, LCX and right coronary artery (RCA) were all higher than 0.85 (p<0.01), and those of RCA, LAD and RCA, and LCX and RCA were between 0.6 and 0.8 (p<0.05). The areas under the receiver operating characteristics curve (AUC) were all higher than 0.90 (p<0.05) in predicting any two coronaries occlusion (<50% and 100%) and three coronaries occlusion (<50%) with a >85% sensitivity and specifcity. Excepting RCA mild occlusion (<50%), AUCs in predicting one coronary occlusion (<50% and 100%) were between 0.7 and 0.9, with >80% sensitivity and specifcity. Conclusions: The coronary sinus fow measured by pulsed Doppler ultrasound can effectively and exactly refect the infusion volume in coronaries, which is a powerful indicator of coronary blood supply.