bluuebunny/crossref_metadata_2025 huggingface dataset:
An Area-Based Matrix Model for Uneven-Aged Forests
Authors: Sallnäs Ola , Berger Ambros , Räty Minna , Trubins Renats
Published: April 2015

In this paper a new concept for modeling uneven-aged forests (UEAF) is presented. The term UEAF in this article encloses all forests that deviate from the even-aged structure. The matrix model is area-based, in that the forest under study is described by a distribution of areas over fixed state-spaces spanned by stem number and volume per hectare classes. Dynamics is introduced as transitions of areas inside the state-space during the simulation. Harvesting activities and the occurrence of calamities are explicitly handled. The model is designed to be suitable for large-scale analyses. The concept was tested in an application to Austrian National Forest Inventory (NFI) data. Results shown, including a comparison to older inventory data, indicate that it is worth further elaborating on the concept and the model. The work will be continued and in the next step the model concept will be applied in several other countries.
Surface Characterization and Photoluminescence Properties of Ce3+,Eu Co-Doped SrF2 Nanophosphor
Authors: Yagoub Mubarak , Swart Hendrik , Noto Luyanda , Bergman Peber , Coetsee Elizabeth
Published: April 2015

SrF2:Eu,Ce3+ nanophosphors were successfully synthesized by the hydrothermal method during down-shifting investigations for solar cell applications. The phosphors were characterized by X-ray diffraction (XRD), scanning Auger nanoprobe, time of flight-secondary ion mass spectrometry (TOF-SIMS), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy. XRD showed that the crystallite size calculated with Scherrer’s equation was in the nanometre scale. XPS confirmed the formation of the matrix and the presence of the dopants in the SrF2 host. The PL of the nanophosphor samples were studied using different excitation sources. The phenomenon of energy transfer from Ce3+ to Eu2+ has been demonstrated.
Titration of DNA/Carbon Nanotube Complexes with Double-Chained Oppositely Charged Surfactants
Authors: Tardani Franco , Mesa Camillo
Published: April 2015

1/1 dispersions of ss-DNA/CNT complexes in mass ratios were investigated in a mixture with didodecyldimethylammonium bromide, DDAB. Depending on the amounts of the surface-active agent and of the complexes, solutions, precipitates, or re-dissolution occur. DDAB titrates the phosphate groups on the outer surface of the complex and controls the phase sequence in these systems. The combination of different experimental methods determined the phases that occur therein. The results are based on optical absorbance, Dynamic Light Scattering, ionic conductivity, ζ-potential, optical microscopy and AFM. From the above findings a (pseudo)-binary phase diagram is attained. The system has strong similarities with polymer-surfactant mixtures. In fact, its properties conform to cases in which interactions between rigid rod-like polyelectrolytes and oppositely charged species take place. The peculiarities of double-chained DDAB in the process imply significant differences with respect to the behavior of single chain surfactants. In fact, DDAB associates into vesicular entities, when the homologous single chain species forms small micellar aggregates.
α-Naphthoflavone Increases Lipid Accumulation in Mature Adipocytes and Enhances Adipocyte-Stimulated Endothelial Tube Formation
Authors: Wang Mei-Lin , Lin Shyh-Hsiang , Hou Yuan-Yu , Chen Yue-Hwa
Published: April 2015

The aryl hydrocarbon receptor (AhR) is a ligand-activated factor that regulates biological effects associated with obesity. The AhR agonists, such as environmental contaminants 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and β-naphthoflavone (BNF), inhibit preadipocyte differentiation and interfere with the functions of adipose tissue, whereas the antagonist may have opposite or protective effects in obesity. This study investigated the effects of α-naphthoflavone (α-NF), an AhR antagonist, on adipogenesis- and angiogenesis-associated factors in mature adipocytes and on cross-talk of mature adipocytes with endothelial cells (ECs). Besides, the roles of the AhR on lipid accumulation and on secretion of vascular endothelial growth factor were also determined by introducing siRNA of AhR. Differentiated 3T3-L1 cells were treated with α-naphthoflavone (α-NF) (1–5 μM) for 16 h. Lipid accumulation and the expressions of AhR-associated factors in the cells were determined. The interaction between adipocytes and ECs was investigated by cultivating ECs with conditioned medium (CM) from α-NF-treated mature adipocytes, followed by the determination of endothelial tube formation. The results showed that α-NF significantly increased triglyceride (TG) accumulation in mature adipocytes, which was associated with increased expression of hormone-sensitive lipase (HSL), estrogen receptor (ER), as well as decreased expression of AhR, AhR nuclear translocator (ARNT), cytochrome P4501B1 (CYP1B1), and nuclear factor erythroid-2-related factor (NRF-2) proteins. In addition, CM stimulated formation of tube-like structures in ECs, and α-NF further enhanced such stimulation in association with modulated the secretions of various angiogenic mediators by mature adipocytes. Similarly, increased TG accumulation and vascular endothelial growth factor (VEGF) secretion were observed in AhR-knockout cells. In conclusion, α-NF increased TG accumulation in mature adipocytes and enhanced mature adipocyte-stimulated tube formation in ECs, suggesting that the AhR may suppress obesity-induced adverse effects, and α-NF abolished the protective effects of the AhR.
Mapping Regional Inundation with Spaceborne L-Band SAR
Authors: Chapman Bruce , McDonald Kyle , Shimada Masanobu , Rosenqvist Ake , Schroeder Ronny , Hess Laura
Published: April 2015

Shortly after the launch of ALOS PALSAR L-band SAR by the Japan Space Exploration Agency (JAXA), a program to develop an Earth Science Data Record (ESDR) for inundated wetlands was funded by NASA. Using established methodologies, extensive multi-temporal L-band ALOS ScanSAR data acquired bi-monthly by the PALSAR instrument onboard ALOS were used to classify the inundation state for South America for delivery as a component of this Inundated Wetlands ESDR (IW-ESDR) and in collaboration with JAXA’s ALOS Kyoto and Carbon Initiative science programme. We describe these methodologies and the final classification of the inundation state, then compared this with results derived from dual-season data acquired by the JERS-1 L-band SAR mission in 1995 and 1996, as well as with estimates of surface water extent measured globally every 10 days by coarser resolution sensors. Good correspondence was found when comparing open water extent classified from multi-temporal ALOS ScanSAR data with surface water fraction identified from coarse resolution sensors, except in those regions where there may be differences in sensitivity to widespread and shallow seasonal flooding event, or in areas that could be excluded through use of a continental-scale inundatable mask. It was found that the ALOS ScanSAR classification of inundated vegetation was relatively insensitive to inundated herbaceous vegetation. Inundation dynamics were examined using the multi-temporal ALOS ScanSAR acquisitions over the Pacaya-Samiria and surrounding areas in the Peruvian Amazon.
Infrared Thermal Imaging System on a Mobile Phone
Authors: Lee Fu-Feng , Chen Feng , Liu Jing
Published: April 2015

A novel concept towards pervasively available low-cost infrared thermal imaging system lunched on a mobile phone (MTIS) was proposed and demonstrated in this article. Through digestion on the evolutional development of milestone technologies in the area, it can be found that the portable and low-cost design would become the main stream of thermal imager for civilian purposes. As a representative trial towards this important goal, a MTIS consisting of a thermal infrared module (TIM) and mobile phone with embedded exclusive software (IRAPP) was presented. The basic strategy for the TIM construction is illustrated, including sensor adoption and optical specification. The user-oriented software was developed in the Android environment by considering its popularity and expandability. Computational algorithms with non-uniformity correction and scene-change detection are established to optimize the imaging quality and efficiency of TIM. The performance experiments and analysis indicated that the currently available detective distance for the MTIS is about 29 m. Furthermore, some family-targeted utilization enabled by MTIS was also outlined, such as sudden infant death syndrome (SIDS) prevention, etc. This work suggests a ubiquitous way of significantly extending thermal infrared image into rather wide areas especially health care in the coming time.
Changes in Arable Land Demand for Food in India and China: A Potential Threat to Food Security
Authors: Nath Reshmita , Luan Yibo , Yang Wangming , Yang Chen , Chen Wen , Li Qian , Cui Xuefeng
Published: April 2015

India and China are two similar developing countries with huge populations, rapid economic growth and limited natural resources, therefore facing the massive pressure of ensuring food security. In this paper, we will discuss the food security situations in these two countries by studying the historical changes of food supply-demand balance with the concept of agricultural land requirements for food (LRF) from 1963–2009. LRF of a country is a function of population, per capita consumption/diet, cropping yield and cropping intensity. We have attempted to discuss and compare our results in a framework which links consumption of different groups of food items to diet patterns; then, to the total land requirement for food in a scenario when population is growing rapidly and diet diversification and urbanization due to economic reform impose excessive pressure on food security of both countries. We also elaborate on the role of technology dissemination and critically analyze the achievements and drawbacks of government policies to ensure food self-sufficiency and food security of nations. Our results show that the total LRF increases approximately by 42% and 40%, whereas per capita LRF decreases significantly by about 48% and 30% from 1963–2009, for India and China, respectively. Furthermore, our studies reveal that population growth dominates most of the increase in total LRF for India; whereas diet pattern change induced by income growth drives the major increase in LRF for China. Therefore, sustainable management of agricultural land resource is an urgent need both for India and China as there will be demand for more food to meet the diet requirement for the entire population. We also demonstrate the role of India and China in future global food security programs and the challenges to implement the new land reform policies domestically.
A Study on the Effect of Nano Alumina Particles on Fracture Behavior of PMMA
Authors: Sezavar Arezou , Zebarjad Seyed , Sajjadi Seyed
Published: April 2015

In the current research, the role of nano-sized alumina on deformation and fracture mechanism of Poly Methyl Methacrylate (PMMA) was investigated. For this purpose, PMMA matrix nanocomposite reinforced with different wt% of alumina (i.e., 5, 10 and 15) were fabricated using the compression molding technique. Tensile properties of produced nanocomposites were studied using Zwick Z250 apparatus at cross head speed of about 5 mm/min. In order to specify the role of alumina nanoparticles on deformation and fracture mechanism of PMMA, microscopic evaluation was performed using scanning electron microscope (SEM). The achieved results prove that tensile properties of PMMA depend on alumina wt%. For example, addition of 15 wt% alumina to PMMA causes an increase of about 25% modulus of elasticity. Micrographs taken from the fracture surface of PMMA and its nanocomposites show deformation and fracture mechanism of PMMA changes as alumina is added to it.
Bioactive Components in Fish Venoms
Authors: Ziegman Rebekah , Alewood Paul
Published: April 2015

Animal venoms are widely recognized excellent resources for the discovery of novel drug leads and physiological tools. Most are comprised of a large number of components, of which the enzymes, small peptides, and proteins are studied for their important bioactivities. However, in spite of there being over 2000 venomous fish species, piscine venoms have been relatively underrepresented in the literature thus far. Most studies have explored whole or partially fractioned venom, revealing broad pharmacology, which includes cardiovascular, neuromuscular, cytotoxic, inflammatory, and nociceptive activities. Several large proteinaceous toxins, such as stonustoxin, verrucotoxin, and Sp-CTx, have been isolated from scorpaenoid fish. These form pores in cell membranes, resulting in cell death and creating a cascade of reactions that result in many, but not all, of the physiological symptoms observed from envenomation. Additionally, Natterins, a novel family of toxins possessing kininogenase activity have been found in toadfish venom. A variety of smaller protein toxins, as well as a small number of peptides, enzymes, and non-proteinaceous molecules have also been isolated from a range of fish venoms, but most remain poorly characterized. Many other bioactive fish venom components remain to be discovered and investigated. These represent an untapped treasure of potentially useful molecules.
NMR Structure of the Myristylated Feline Immunodeficiency Virus Matrix Protein
Authors: Brown Lola , Cox Cassiah , Baptiste Janae , Summers Holly , Button Ryan , Bahlow Kennedy , Spurrier Vaughn , Kyser Jenna , Luttge Benjamin , Kuo Lillian , Freed Eric , Summers Michael
Published: April 2015

Membrane targeting by the Gag proteins of the human immunodeficiency viruses (HIV types-1 and -2) is mediated by Gag’s N-terminally myristylated matrix (MA) domain and is dependent on cellular phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2]. To determine if other lentiviruses employ a similar membrane targeting mechanism, we initiated studies of the feline immunodeficiency virus (FIV), a widespread feline pathogen with potential utility for development of human therapeutics. Bacterial co-translational myristylation was facilitated by mutation of two amino acids near the amino-terminus of the protein (Q5A/G6S; myrMAQ5A/G6S). These substitutions did not affect virus assembly or release from transfected cells. NMR studies revealed that the myristyl group is buried within a hydrophobic pocket in a manner that is structurally similar to that observed for the myristylated HIV-1 protein. Comparisons with a recent crystal structure of the unmyristylated FIV protein [myr(-)MA] indicate that only small changes in helix orientation are required to accommodate the sequestered myr group. Depletion of PI(4,5)P2 from the plasma membrane of FIV-infected CRFK cells inhibited production of FIV particles, indicating that, like HIV, FIV hijacks the PI(4,5)P2 cellular signaling system to direct intracellular Gag trafficking during virus assembly.
Preliminary Toxicological Evaluation of the River Danube Using in Vitro Bioassays
Authors: Kittinger Clemens , Baumert Rita , Folli Bettina , Lipp Michaela , Liebmann Astrid , Kirschner Alexander , Farnleitner Andreas , Grisold Andrea , Zarfel Gernot
Published: April 2015

The Joint Danube Survey 3, carried out in 2013 was the world’s biggest river research expedition of its kind. The course of the second largest river of Europe passes large cities like Vienna, Budapest and Belgrade and is fed from many tributaries like Inn, Thisza, Drava, Prut, Siret and Argeș. During the 6 weeks of shipping the 2375 km downstream the River Danube from Germany to the Black Sea an enormous number of water samples were analyzed and collected. A wide spectrum of scientific disciplines cooperated in analyzing the River Danube waters. For toxicological analysis, water samples were collected on the left, in the middle, and on the right side of the river at 68 JDS3 sampling points and frozen until the end of the Danube survey. All samples were analyzed with two in vitro bioassays tests (umuC and MTS). Testing umuC without S9 activation and MTS test did not show positive signals. But umuC investigations of the water samples came up with toxic signals on two stretches, when activated with S9 enzymes. The override of the limiting value of the umuC investigation with prior S9 activation started downstream Vienna (Austria) and was prolonged until Dunaföldvar (Hungary). This stretch of the River Danube passes a region that is highly industrialized, intensively used for agricultural purposes and also highly populated (Vienna, Bratislava and Budapest). The elevated values may indicate these influences.
FRAMEWORK FOR INTEGRATING INDOOR AIR QUALITY IMPACTS INTO LIFE CYCLE ASSESSMENTS OF BUILDINGS AND BUILDING RELATED PRODUCTS
Authors: Wu Susie R. , Apul Defne
Published: April 2015

Products used during construction and operation of a building can contribute to Indoor Air Quality (IAQ) problems that affect occupants' well-being. However, IAQ is conventionally not addressed in the life cycle assessments (LCAs) of buildings and building related products even though IAQ leads to one of the areas of protection under LCA - human health impacts. In this study, we proposed an overall framework for integrating IAQ into LCA using the standard steps of LCA. The framework focused on IAQ and LCA modeling from two categories of building related products: i) passive products that realize their function through initial installation and have long-term decayed emissions, and ii) active equipment that realize their function and cause emissions through daily operation. Dynamic and static life cycle inventory modeling approaches were proposed for passive products and active equipment, respectively. An indoor intake fraction equation and USEtox model effect factors were incorporated into the life cycle impact assessment. Three hypothetical examples were presented to illustrate the calculation procedure of the framework. We concluded that it was feasible to integrate IAQ into building related LCA studies. Development of IAQ related impact assessment methodologies can improve upon the limitations of this study. Further studies need to be carried out to compare the health impacts from IAQ related sources to other life cycle stages of building related products.
PATIENT EXPERIENCE WITH HOSPITAL CARE - COMPARISON OF A SAMPLE OF GREEN HOSPITALS AND NON-GREEN HOSPITALS
Authors: Sadatsafavi Hessam , Walewski John , Taborn Michael
Published: April 2015

Although the sustainability movement in the healthcare sector was initiated in response to ecological concerns, green hospitals are expected to outperform traditional hospitals on a variety of levels. The impacts of environmental quality on patients and caregivers are demonstrated in numerous studies. However, there is still a lack of evidence on the benefits of green hospitals with respect to different dimensions of patients' experiences. In this study, data from the public Hospital Consumer Assessment of Health Plans Survey is used to compare the performance of green hospitals with the average performance of traditional hospitals. This study included 19 green hospitals and found that patients hospitalized in green facilities reported overall higher ratings than those in traditional hospitals when compared to the average performance of traditional hospitals of similar sizes and locations. Additionally, patients in green hospitals were more likely to recommend the hospital to their friends and family. However, relationships between specific green building features and patient experiences were not identified in this study.
Rigid and Flexible Dynamics Simulation of 2-PRR Parallel Mechanism
Authors: Chen Chun , Liu Er Yue , Chen Zi Wei , Wang Qing Liang , Huang Yu Mei
Published: April 2015

After using three-dimensional software for the 2-PRR parallel mechanism modeled into ADAMS, and on one of the links in ANSYS is flexible processing of replacing the rigid rod. In ADAMS/View environment using kinematics and dynamics simulation for the 2-PRR parallel mechanism, verification of positive solution and inverse of the mechanism, and get the characteristic curves of driven torque changes of driven slider. The study concludes that parallel mechanism in engraving and milling machine tools and robots in plane design and selection provides a theoretical basis.
Research on Piezoelectric Generators for Vibration Energy Harvesting
Authors: Zhou Kai , Xie Fang , Tao Yi , Du Hai Xia
Published: April 2015

Ambient energy harvesting has been in recent years the recurring object of a number of research efforts aimed at providing an autonomous solution to the powering of small scale electronic mobile devices. Among the different solutions, vibration energy harvesting has played a major role due to the almost universal presence of mechanical vibrations. In the paper, a piezoelectric cantilever device for harvesting the ambient low-frequency vibration energy is designed, and influences of its structure on output voltage and power generation capacity are studied also. The study results show that the piezoelectric cantilever can produce enough power energy which meets the operation requirements of sensors in wireless networks. It provides a method and corresponding theoretical basis for the harvesting of ambient low-frequency vibration energy and the design of self-supply devices for sensors in wireless networks.
Study on the Energy Recovery Ability of Hybrid Tractor Based on Advisor
Authors: Yang Li Hao , Wang You Jun , Lv Qiu Juan
Published: April 2015

Energy recovery ability is one of the most important ability of the hybrid system. In this paper, we established a simulation model of a 10T hybrid tractor under researching in advisor by the secondary development technology. And then we carried out the simulation which provides many important curves about the energy recovery ability and some other important abilities under the working conditions of 5 peak cycle using the self-adaptive fuzzy control strategy. The results of the simulation prove that the recovery ability of the hybrid tractor satisfy the design goals well.
Research on the Stress Intensity Factor of the Cracks in the Spherical Shell
Authors: Chen Fei , Yue Ying Juan , Zhang Cui Ping , Du Hai Xia
Published: April 2015

Three models including scheme A, B and C of the semicircular or crescent surface cracks, and two ones including scheme D and E of elliptical inner cracks in the vessel wall in three-dimensional are estabished with ABAQUS software. The values of the crack tip of the stress intensity factor are calculated and compared with the empirical results based on BS 7910 standard. The results show that scheme C and D are better, which provide a new method for the modeling and simulation of three-dimensional components containing cracks with finite element method.
A New Type ADAMS-Based Virtual Prototype of Folding-Arm Gondola
Authors: Tao Yi , Xie Fan , Guo Jian Feng , Zhou Kai , Wang Xin Feng
Published: April 2015

This paper has introduced the method how to establish a model for the virtual prototype of new type folding-arm gondola CD 250 based on the ADAMS technology, then to do analyses and inspection for the built virtual prototype, and to combine the test results with the traditional DOF calculation to sum up the feasible calculation method for DOF, finally, further verify the rationality of the model, which provides the necessary foundation for subsequently utilizing the virtual prototype technology to analyze the working condition of the gondola.
Simulation Research on Steering Qualities of Loader Fitted with Rubber Tracks Based on Virtual Prototype Technology
Authors: Wang You Jun , Yang Li Hao
Published: April 2015

The steering quality is one of the most important targets which reflect the flexibility of the vehicles. In this paper, the basic composition of the changeable tracks was introduced and then a virtual prototype of the shovel loader with four tracks was established according to the truth designing dimensions. After which the simulation was done to analysis it’s steering qualities. The results indicate that the shovel loader with four tracks have strong maneuverability and stability when turning around. This simulation provides theory supports for the further research of this new kind of tread structure.
Research and Development of Nanoimprint Lithography Technology
Authors: Chen Jian Gang , Liu Li Jun , Zhao Zhi Xin , Liu Ju Rong
Published: April 2015

This paper introduces research situation and prospect of nanoimprint lithography technology. The process of three common lithography (Such as hot press printing, UV curing stamping and Micro Contact stamping) is discussed. For getting better quality, the method and main factors of nanoimprint lithography pattern are analyzed. Furthermore, some key problems of the nanoimprint lithography process are solved for the purpose of the further understands for this process. A new way of thinking is provided for development new nanoimprint lithography technology in the paper.
The Effect of Hollow Glass Reinforced Epoxy in Absorbing Impact Energy for Vehicle Bumper Application
Authors: Amalia Hindun , Sutikno  , Sidharta Indra , Wijanarko Wahyu , Suwarta Putu
Published: April 2015

Safety is one of important factors which has to be considered in designing automobile in the automotive industry. One of the components related to the automobile safety is bumper. Bumpers are attached on front and rear of vehicle’s body in order to protect the body from damage due to low speed crash. In this research, hollow glass microsphere (HGM) reinforced epoxy is used as the material for the bumper since this material has not been applied to this application yet. This research is conducted in order to find the ability of this composite material in absorbing impact energy from low speed crash by using finite element method. Thickness of the bumper varied from 4 mm to 8 mm with 1 mm increment. Low speed collision is simulated by following Economic Commission for Europe Regulation 42. The bumper energy absorption is analyzed and indicated by the internal energy, deformation, and equivalent stress from each bumper’s thickness.
Fabrication of Bicycle Frame of A356 Aluminum Alloys by Using Sand Casting
Authors: Suyitno  , Salim Urip Agus
Published: April 2015

Bicycle frames on the market are generally made from a pipe connected by welding process. Bicycles are made by big companies, because it requires forming technology of raw materials for the pipe production and complex welding technologies. In order to reduce the dependence on raw materials and pipe welding processes, an alternative technology for bicycle frame manufacturing process is investigated. This study is aimed to examine the use of casting technology in the manufacturing process of bicycle frame. Production of bicycle frames in limited quantities is possible by using the casting process. To achieve these objectives, it is necessary to redesign the bicycle frame suitable for the casting process. Prototypes have been produced and the first bike is in the testing phase. Initilly , the bicycle is relatively heavy (7 kg). The optimization of the design reduces to a light and strong frame. The frame has a weight of 3.74 kg. The prototype of the frame has been succesfully casted by sand casting method.
Comparative Study on Performance of Very Low Head Axial Hydraulic Turbine Using a Single Rotor and a Contra-Rotating Rotor
Authors: Muis Abdul , Sutikno Priyono , Suwono Aryadi , Hartono Firman
Published: April 2015

Studies conducted on axial flow hydraulic turbine by comparing the performance of turbines which use a single rotor and two rotors that rotate in opposite (contra-rotating). Both turbines are designed to generate energy utilizing a very low head water flow. Single rotor turbine consists of one row of guide vane and one row of rotor blade. Contra-rotating rotor turbine consists of one row of guide vane and two rows of rotor blade, which is the front rotor blade also serves as a guide vane for the rear rotor. Both of turbines are designed for the same flow and operating conditions.
The results of numerical studies show that both of turbines can be applied with a fairly high efficiency, however the single rotor turbine is significantly higher. Especially for contra-rotating turbine, the total power that generated at the same operating conditions will increase because powers are resulted from both of rotors, but the effective head required will be significantly increase compare to the single-rotor turbine. These results may be used as a reference in the development of axial flow hydraulic turbine for very low head sites to expand the applications.
Keywords: Single rotor, contra-rotating rotor, axial flow, very low head, hydraulic turbine.
Stiffness Effect on Low-Frequency Stick-Slip Motion Generated on a Simple Caliper-Slider Experimental Model
Authors: Fuadi Zahrul , Adachi Koshi
Published: April 2015

This paper discusses the occurrence and non occurrence of low-frequency stick-slip motion on a simple caliper-slider experimental model. The analysis focused on the relationship between stiffness, i.e. contact stiffness and structure’s stiffness, and the generation of stick-slip motion. The occurrence of stick-slip motion is determined by analyzing the frequency characteristic of resulted vibration acceleration at the beginning of sliding which is resulted from a simultaneous application of force in tangential direction and slow release of force in normal direction. The results show that the occurrence and non occurrence of stick-slip motion can be classified into three regions according to the parameter of stiffness ratio, i.e. non occurrence region, mixed region, and occurrence region. The stiffness ratio Sr, the ratio of contact stiffness Kc to structure’s stiffness Ks, of 40 is found to be critical for the low-frequency stick-slip generation in this experimental model.
Experimental Study on the Effect of Vortex Generator on the Aerodynamic Characteristics of NASA LS-0417 Airfoil
Authors: Sutardi S. , Nurcahya Agung E.
Published: April 2015

Boundary layer flow structure developing on an airfoil surfaces strongly affects drag and lift forces acting on the body. Many studies have been done to reduce drag, such as introducing surface roughness on the airfoil surface, gas injection, attachment of vortex generators, or moving surface on the airfoil. Previous results showed that the attachment of vortex generators has potentially been able to control boundary layer separation compared to other controlling devices. This study is focused on the evaluation of the effect of vortex generator attachment on the NASA LS-0417 airfoil profile as this profile is commonly used in wind turbine blade application.
The models of this experimental study are NASA LS-0417 profiles, with and without vortex generator. The chord length of the profile is 110 mm, while the span is 210 mm. Profile of the vortex generator is a symmetrical profile of NACA 0012 configured in counter rotating and attached on the upper surface of the main profile. The chord length of the vortex generator is 7 mm with two different values of the height (h): 1 mm and 2 mm. The experiment was conducted in an open loop wind tunnel with maximum attainable freestream velocity of approximately 19 m/s and the turbulence intensity at the tunnel centerline is approximately 0.8%. The wind tunnel cross section is octagonal of 30 cm x 30 cm and of 45 cm to 60 cm adjustable length. The study was performed at two different freestream velocities of 12 m/s and 17 m/s corresponding with Reynolds numbers (Re) of 0.83 x 105 and 1.18 x 105 based on the airfoil chord length and the freestream velocity. Angle of attact (α) was varied from 0o to 24o. Drag and lift were measured using a force balance with measurement uncertainty of approximately 0.77% and 2.47% at measured drag of 0.65N and at measured lift of 0.202N, respectively. A flow visualization study using oil flow method was conducted to obtain qualitaive picture of flow structure on the airfoil surface.
Results of this study showed that attachment of the vortex generator on the NASA LS-0417 profile has not been able to improve the profile performance compared to that of unmodified profile. There, however, seems Reynolds number effect on the airfoil performance flow conditions performed in this study. At lager Re, there is an increase in CL/CD of approximately 36% at angle of attack (α) 6o. Next, based on the flow visualization results, attachment of the 2mm vortex generator on the airfoil NASA LS-0417 surface results in an advancement of boundary layer separation at the two Re’s conducted in this study. Finally, the 2mm vortex generator accelerates airfoil stall at approximately 16o, while the 1mm vortex generator is relatively no effect on the airfoil stall angle.
Effect Pouring Temperature on Casting Defect Susceptibility of Hot Tearing in Metal Alloy Al-Si
Authors: Hasan Akhyar , Suyitno
Published: April 2015

Hot tearing is one of metal casting defects and often found in the casting products such as cracks on the surface. Solidifaction metal causes a thermal contraction and shrinkage, when the contraction and shrinkage occurs if a metal alloy is restrained by mold design, it will effect hot tearing. Hot tearing is influenced by several factors, including the chemical composition of the alloy, the casting temperature, mold temperature, mold constraint, fast or slow solidifaction, non uniform solidifaction, and so on. This study aimed to obtain a certain temperature that cause the maximum of hot tearing defects, so it can be recommended to the metal casting industry in aluminum-silicon material to avoid the casting temperature. Three variations of the casting temperature used in this study including 710 oC, 760 oC and 810 oC. The material used in this study is an alloy of Al-1.19% Si (percent by weight). The method used is a visual method using mold CRCM (Constrain Casting Rod Modified) Horizontal used for the index analysis of HTS (Hot tearing Susceptibility). The results gotten include the hot tearing increases with the increasing of casting temperature, and it decreases with the decreasing the casting pouring. The maximum of hot tearing index is 45 HTS at 760 oC for casting temperature. Tear formed on products from smooth categories (hairline cracks) to the complete categories (broken specimen).
Mature Cystic Fibrosis Airway Neutrophils Suppress T Cell Function: Evidence for a Role of Arginase 1 but Not Programmed Death-Ligand 1
Authors: Ingersoll Sarah A. , Laval Julie , Forrest Osric A. , Preininger Marcela , Brown Milton R. , Arafat Dalia , Gibson Greg , Tangpricha Vin , Tirouvanziam Rabindra
Published: April 2015

Bacteria colonize cystic fibrosis (CF) airways, and although T cells with appropriate Ag specificity are present in draining lymph nodes, they are conspicuously absent from the lumen. To account for this absence, we hypothesized that polymorphonuclear neutrophils (PMNs), recruited massively into the CF airway lumen and actively exocytosing primary granules, also suppress T cell function therein. Programmed death–ligand 1 (PD-L1), which exerts T cell suppression at a late step, was expressed bimodally on CF airway PMNs, delineating PD-L1hi and PD-L1lo subsets, whereas healthy control (HC) airway PMNs were uniformly PD-L1hi. Blood PMNs incubated in CF airway fluid lost PD-L1 over time; in coculture, Ab blockade of PD-L1 failed to inhibit the suppression of T cell proliferation by CF airway PMNs. In contrast with PD-L1, arginase 1 (Arg1), which exerts T cell suppression at an early step, was uniformly high on CF and HC airway PMNs. However, arginase activity was high in CF airway fluid and minimal in HC airway fluid, consistent with the fact that Arg1 activation requires primary granule exocytosis, which occurs in CF, but not HC, airway PMNs. In addition, Arg1 expression on CF airway PMNs correlated negatively with lung function and positively with arginase activity in CF airway fluid. Finally, combined treatment with arginase inhibitor and arginine rescued the suppression of T cell proliferation by CF airway fluid. Thus, Arg1 and PD-L1 are dynamically modulated upon PMN migration into human airways, and, Arg1, but not PD-L1, contributes to early PMN-driven T cell suppression in CF, likely hampering resolution of infection and inflammation.
Determination of the optimal time of vaccination against infectious bursal disease virus (Gumboro) in Algeria
Authors: Besseboua Omar , Ayad Abdelhanine , Benbarek Hama
Published: April 2015

This study was conducted to determine the effect of maternally derived antibody (MDA) on live vaccine against infectious bursal disease. A total of 140 chicks selected from vaccinated parent stock were used in this investigation. In a preset vaccination schedule, blood samples were collected to check for the actual effect. It was noticed that on day 1 the chicks contained a high level (6400.54 ± 2993.67) of maternally derived antibody that gradually decreased below a positive level within 21 days (365.86 ± 634.46). It was found that a high level of MDA interferes with the vaccine virus, resulting in no immune response. For better immune response, it is suggested that the chickens should be vaccinated at day 21, as the uniformity of MDA is poor (coefficient of the variation [CV] > 30%), and boosted at day 28. Indeed, two vaccinations are necessary to achieve good protection against infectious bursal disease virus of the entire flock.
Dopluise (Hemiptera: Coccoidea) geassosieer met die wipstertmier, Crematogaster peringueyi Emery (Hymenoptera: Formicidae)
Authors: Giliomee Johannes H.
Published: April 2015

Nests of the cocktail ant, Crematogaster peringueyi (Hymenoptera: Formicidae), were collected from various locations along the coast of the Western Cape. The purpose was to determine which scale insects (Hemiptera: Coccoidea) live in association with these ants. Scale insects of three families, that is, Pseudococcidae (mealy bugs), Coccidae (soft scales) and Kerriidae (lac scales) were found in the nests, all of them known for secreting honeydew. This mutualistic association between the ants and scale insects, known as myrmecophily, is facultative, as the cocktail ant and the scale insects were also both found separately. The cocktail ant does not appear to be selective in choosing a plant on which to build a nest.
Simulation of Acoustic Behavior of Bubbly Liquids with Hybrid Lattice Boltzmann and Homogeneous Equilibrium Models
Authors: Chen Xiao-Peng , Liu Ming
Published: April 2015

Homogeneous equilibrium model (HEM) has been widely used in cavitating flow simulations. The major feature of this model is that a single equation of state (EOS) is proposed to describe the thermal behavior of bubbly liquid, where both kinematic and thermal equilibrium is assumed between two phases. In this paper, the HEM was coupled with multi-relaxation-time lattice Boltzmann model (MRT-LBM) and the acoustic behavior was simulated. Two approaches were applied alternatively: adjusting speed of sound (Buick, J. Phys. A, 2006, 39:13807-13815) and setting real gas EOS. Both approaches result in high accuracy in acoustic speed predictions for different void (gas) volume of fractions. It is demonstrated that LBM could be successfully applied as a Navier-Stokes equation solver for industrial applications. However, further dissipation and dispersion analysis shows that Shan-Chen type approaches of LBM are deficient, especially in large wave-number region.
Computational Modeling of Membrane Viscosity of Red Blood Cells
Authors: Gounley John , Peng Yan
Published: April 2015

Despite its demonstrated importance in the deformation and dynamics of red blood cells, membrane viscosity has not received the same attention in computational models as elasticity and bending stiffness. Recent experiments on red blood cells indicated a power law response due to membrane viscosity. This is potentially much different from the solid viscoelastic models, such as Kelvin-Voigt and standard linear solid (SLS), currently used in computation to describe this aspect of the membrane. Within the context of a framework based on lattice Boltzmann and immersed boundary methods, we introduce SLS and power law models for membrane viscosity. We compare how the Kelvin-Voigt (as approximated by SLS) and power law models alter the deformation and dynamics of a spherical capsule in shear flows.
Lattice Boltzmann Schemes with Relative Velocities
Authors: Dubois François , Fevrier Tony , Graille Benjamin
Published: April 2015

In this contribution, a new class of lattice Boltzmann schemes is introduced and studied. These schemes are presented in a framework that generalizes the multiple relaxation times method of d’Humières. They extend also the Geier’s cascaded method. The relaxation phase takes place in a moving frame involving a set of moments depending on a given relative velocity field. We establish with the Taylor expansion method that the equivalent partial differential equations are identical to the ones obtained with the multiple relaxation times method up to the second order accuracy. The method is then performed to derive the equivalent equations up to third order accuracy.
Compilation of Henry's law constants (version 4.0) for water as solvent
Authors: Sander R.
Published: April 2015

Abstract. Many atmospheric chemicals occur in the gas phase as well as in liquid cloud droplets and aerosol particles. Therefore, it is necessary to understand the distribution between the phases. According to Henry's law, the equilibrium ratio between the abundances in the gas phase and in the aqueous phase is constant for a dilute solution. Henry's law constants of trace gases of potential importance in environmental chemistry have been collected and converted into a uniform format. The compilation contains 17 350 values of Henry's law constants for 4632 species, collected from 689 references. It is also available at http://www.henrys-law.org.
Large-eddy simulations of surface roughness parameter sensitivity to canopy-structure characteristics
Authors: Maurer K. D. , Bohrer G. , Kenny W. T. , Ivanov V. Y.
Published: April 2015

Abstract. Surface roughness parameters, namely the roughness length and displacement height, are an integral input used to model surface fluxes. However, most models assume these parameters to be a fixed property of plant functional type and disregard the governing structural heterogeneity and dynamics. In this study, we use large-eddy simulations to explore, in silico, the effects of canopy-structure characteristics on surface roughness parameters. We performed a virtual experiment to test the sensitivity of resolved surface roughness to four axes of canopy structure: (1) leaf area index, (2) the vertical profile of leaf density, (3) canopy height, and (4) canopy gap fraction. We found roughness parameters to be highly variable, but uncovered positive relationships between displacement height and maximum canopy height, aerodynamic canopy height and maximum canopy height and leaf area index, and eddy-penetration depth and gap fraction. We also found negative relationships between aerodynamic canopy height and gap fraction, as well as between eddy-penetration depth and maximum canopy height and leaf area index. We generalized our model results into a virtual "biometric" parameterization that relates roughness length and displacement height to canopy height, leaf area index, and gap fraction. Using a decade of wind and canopy-structure observations in a site in Michigan, we tested the effectiveness of our model-driven biometric parameterization approach in predicting the friction velocity over heterogeneous and disturbed canopies. We compared the accuracy of these predictions with the friction-velocity predictions obtained from the common simple approximation related to canopy height, the values calculated with large-eddy simulations of the explicit canopy structure as measured by airborne and ground-based lidar, two other parameterization approaches that utilize varying canopy-structure inputs, and the annual and decadal means of the surface roughness parameters at the site from meteorological observations. We found that the classical representation of constant roughness parameters (in space and time) as a fraction of canopy height performed relatively well. Nonetheless, of the approaches we tested, most of the empirical approaches that incorporate seasonal and interannual variation of roughness length and displacement height as a function of the dynamics of canopy structure produced more precise and less biased estimates for friction velocity than models with temporally invariable parameters.
A global approach to defining flood seasons
Authors: Lee D. , Ward P. , Block P.
Published: April 2015

Abstract. Globally, flood catastrophes lead all natural hazards in terms of impacts on society, causing billions of dollars of damages annually. While short-term flood warning systems are improving in number and sophistication, forecasting systems on the order of months to seasons are a rarity, yet may lead to further disaster preparedness. To lay the groundwork for prediction, dominant flood seasons must be adequately defined. A global approach is adopted here, using the PCR-GLOBWB model to define spatial and temporal characteristics of major flood seasons globally. The main flood season is identified using a volume-based threshold technique. In comparison with observations, 40% (50%) of locations at a station (sub-basin) scale have identical peak months and 81% (89%) are within 1 month, indicating strong agreement between model and observed flood seasons. Model defined flood seasons are additionally found to well represent actual flood records from the Dartmouth Flood Observatory, further substantiating the models ability to reproduce the appropriate flood season. Minor flood seasons are also defined for regions with bi-modal streamflow climatology. Properly defining flood seasons can lead to prediction through association of streamflow with local and large-scale hydroclimatic indicators, and eventual integration into early warning systems for informed advanced planning and management. This is especially attractive for regions with limited observations and/or little capacity to develop early warning flood systems.