bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Simulations of Filling Flows in Die-Casting Molding of the Thin-Walled LED Heat Sink
Authors: Jou Rong-Yuan
Published: October 2014

In this study, the mold filling analyses of a thin-walled LED heat sink combined with the vacuum valve runner are simulated by FLOW-3D software. Two topics are analyzed and discussed. First, numerical simulations for variety of molding conditions, including effects of thermal conductivity, vacuum pumping pressure, mold temperature, filling velocity, respectively, are conducted for the computational model of the thin-walled LED heat sink connected with the vacuum shut-off valve. Second, effects of several geometrical parameters, including fin thicknesses of the LED heat sink and dimensions of the vacuum shut-off valve are explored. In these two topics, melts are set to liquid metal of Al 384.0 materials. The first topic of analysis mainly to investigate the effects of molding parameters based upon the same computational model of the thin-walled LED heat sink connected with a vacuum valve runner. The simulated results show if molding conditions are changed, different sizes of defects are appeared in castings; if vacuum pumping pressure is higher, the casting is also firmness, density prone to increase; if vacuum pumping pressure is too low, then pumping efficiency of mold cavity is low and it will be easy to form the casting porosity defects. For the second topic of analysis, molding conditions are hold constantly, and effects of different geometrical dimensions to castings qualifications are simulated. Characteristic dimension of trigger mechanism can effectively operate the vacuum shut-off function; but too thin or too thick of channel, it will affect the pumping time if different degrees of vacuum is imposed. Decreasing of gas residuals in castings for the vacuum pumping pressures of 760Torr, 200Torr, 100Torr compared with 10Torr, were 0.311%, 0.174%, 0.008%, respectively. It shows the appropriate and effective vacuum level for vacuum die-casting of the thin-walled LED heat sink is in the range of 100Torr.
Functional Recovery of the Upper Limb With an Active Personal Device
Authors: Casolo Federico , Savalli Gianluca
Published: October 2014

A new personal device to assist the upper limb capable to be mounted on a wheelchair is being tested. The robot is equipped with three brushless motors powered by four electronic boards appositely designed and communicating via I2C protocol; one board works as master for the other three, which have simpler tasks. Most of the driving software has been developed with Matlab and mainly translated into C++ for memory space and boards’ efficiency matters. The system’s end-effector is connected to the subject’s forearm and can cooperate to the arm motion in several different ways. In order to avoid the overstress of the natural joints no further connections are made to the upper limb. The working volume of the limb connected to the device allows the execution of the trajectories required for most of daily living activities. It is addressed to post stroke rehabilitation and to the self-treatment of other patients with serious deficiency of arm forces, like individuals affected by muscular dystrophy. Some working modes exploit the mechanical impedance control to gently interfere with the residual natural motion capability of the subjects. The very preliminary tests of the prototype fitted on a power wheelchair are encouraging: it is light, not too noisy and easy to move for the subject. The first working mode, with full arm gravity compensation, and the second working mode, with partial compensation, have been implemented and are currently being tested with patients, as well as the mode in which the subject is helped to repeat a stereotyped exercise for self-physiotherapy. Beside the fact the control system must be calibrated on patient characteristics, for these initial tasks the system reveals to be user-friendly. Other working modes require to interpret the patient intention to move the upper limb. For a natural approach it is sufficient to decode the movement intention of the patient and the final position he wants the hand to reach, whilst the rest of the limb can be automatically positioned by the system. Different approaches to solve the problem have been experimentally tested, including the use of a headgear with a brain interface. To present knowledge the best results have been obtained by monitoring the movement of another body segment such as the head. The device designed for the functional recovery of upper limb can furthermore be used to monitor and easily certify the evolution of the patient conditions.
Uniform Equations in the Inlet and Exit Zones of Heavily Loaded Point EHL Contacts Involved in Various Steady Motions
Authors: Kudish Ilya I.
Published: October 2014

Heavily loaded point EHL contacts involved in steady purely transitional, skewed transitional, and transitional with spinning motions are considered. It is shown that in the central parts of the inlet and exit zones of such heavily loaded point EHL contacts the asymptotic equations governing the EHL problem along the lubricant flow streamlines for the above types of contact motions can be reduced to two sets of asymptotic equations: one in the inlet and one the exit zones. The latter sets of equations are identical to the asymptotic equations describing lubrication process in the inlet and exit zones of the corresponding heavily loaded line EHL contact [1]. For each specific motion of a point contact a separate set of formulas for the lubrication film thickness is obtained. For different types of contact motions these film thickness formulas differ significantly [1]. For heavily loaded contacts the discovered relationship between point and line EHL problems allow to apply to point contacts most of the results obtained for line contacts [1,2].
Inverse Dynamic and Control of a Hybrid Parallel Robot
Authors: Rakhodaei Hamid , Saadat Mozafar
Published: October 2014

In this paper, a new methodology for the development of the dynamic formulation for a hybrid parallel robot is introduced. The robot includes a tripod that is serially connected on top of a hexapod in order to increase its overall workspace, while maintaining sufficient accuracy and stiffness in motion. The robot will have applications involving gripping and manipulation of large aerospace components such as a wingbox structures and panels. The dynamic formulation of the system, based on Newton-Euler and inverse kinematic equations, is presented by identifying the position vector of the actuators during motion when the system follows certain point and orientation in space. Based on the velocity and acceleration, calculated by taking derivative of the motion equation, the force on the actuator is identified. Since the position vectors of all tripod joints can change through motion, the above methodology offers less complex calculations compared with the existing methods such as using forward dynamics. A MATLAB software was developed to create a set of comprehensive dynamic equations for the overall control system design. An experimental physical hybrid robot was built in order to verify the theoretical formulations. Force sensors, connected at each actuator joint, were used to obtain the applied force on each actuator through a number of given motions. The applied forces subsequently assist to calculate the acceleration of the moving platform. The experimental actuators’ force results compare well with the proposed theoretical formulation.
A Parametric Investigation of Jet and Vortex Actuator
Authors: Cadirci Sertac , Gunes Hasan
Published: October 2014

The Jet and Vortex Actuator (JaVA) is a zero-net-mass flux device for active flow control. In this numerical study, we present a parametric study of JaVA in quiescent water and obtain time-averaged flow and vorticity fields. We systematically investigate the effect of the governing parameters that affect on the JaVA - induced flow characteristics. Three jet Reynolds numbers are investigated in detail; ReJ = 68, 150 and 250 and for each jet-Reynolds number, four different wide-slot to plate width ratios are considered: gw = 0. 0166, 0.0338, 0.066 and 0.10. In all cases, the scaled amplitude is kept at Sa = 0.15 and 0.30 so that a total of 24 different simulations are investigated. JaVA - induced flow types are classified in five groups: wall-jet, vertical-oblique jet, chaotic jet, weak jet and vortex mode. Based on the governing parameters (Sa, ReJ and gw) all these flow types have been identified the jet-momentums are calculated from phase-averaged jet velocities obtained from numerical modeling results and compared to each other. It is found that generally the vortex mode transports the highest momentum flux followed by a chaotic jet.
Thermodynamic Analysis of a Compressed Air Energy Storage Facility Exporting Compression Heat to an External Heat Load
Authors: Safaei Hossein , Aziz Michael J.
Published: October 2014

Fluctuations of electric load call for flexible generation technologies such as gas turbines. Alternatively, bulk energy storage (BES) facilities can store excess off-peak electricity to generate valuable peaking electricity. Interest in electricity storage has increased in the past decade in anticipation of higher penetration levels of intermittent renewable sources such as wind. Compressed Air Energy Storage (CAES) is one of the most promising BES technologies due to the large amount of energy (hundreds of MWh) that can be economically stored. CAES uses off-peak electricity to compress air into underground reservoirs. Air is combusted and expanded at a later time to regenerate electricity. One of the downsides of CAES is the large energy losses incurred in the form of waste compression heat. Distributed CAES (D-CAES) has been proposed in order to improve the roundtrip efficiency of CAES by utilizing the compression heat for space and water heating. The compressor of D-CAES is located near a heat load (e.g. a shopping mall) and the compression heat is recovered to meet this external load. D-CAES collects fuel credits equal to the negated heating fuel, leading to a higher overall efficiency compared to conventional CAES. We perform a thermodynamic analysis of conventional CAES and D-CAES to compare their heat rate, work ratio (electric energy stored per unit of electric energy regenerated), and exergy efficiency.
Topological Shear Stress Optimisation of Micro-CT Based Scaffolds
Authors: Almeida Henrique A. , Bártolo Paulo J.
Published: October 2014

Additive manufacturing technologies are being used to fabricate scaffolds with controlled architecture for tissue engineering applications. These technologies combined with computer-aided design systems enable to produce three-dimensional structures layer-by-layer in a multitude of materials. Actual prediction of the effective mechanical properties of scaffolds produced by Additive manufacturing systems, is very important for tissue engineering applications. One of the existing computer based techniques for scaffold design is topological optimisation. The goal of topological optimisation is to find the best use of material for a body that is subjected to either a single load or a multiple load distribution. This paper proposes a topological optimisation scheme based on existing micro-CT data in order to obtain the ideal topological architectures of scaffolds, maximising its mechanical behaviour under shear stress solicitations. This approach is based on micro-CT data of real biological tissues to create the loading (shear stress) and constraint surfaces of the scaffold during the topological optimisation process. This particular topological optimisation scheme uses the surface boundaries to produce novel models with different characteristics, which are different from the initial micro-CT models. This approach enables to produce valid biomimetic scaffold topologies for tissue engineering applications.
In-Process Quality Characterization of Grinding Processes: A Sensor-Fusion Based Approach
Authors: Maggioni Matteo , Marzorati Elena , Grasso Marco , Colosimo Bianca Maria , Parenti Paolo
Published: October 2014

The quality assessment of manufacturing processes has been traditionally based on sample measures performed on the process output. This leads to the common “product-based Statistical Process Control (SPC)” framework. However, there are applications of actual industrial interest where post-process quality measurement procedures involve time-consuming inspections strongly related to the operator’s experience and/or based on expensive equipment. Cylindrical grinding of large rolls may be one of them. The assessment of the final acceptability of a ground cylinder, in terms of surface finish, is a challenging task with traditional measuring tools, and it often depends on operator’s visual inspections and on his subjective evaluations. In this frame, a paradigm shift is required to substitute troublesome post-process monitoring procedures with in-process and signal-based ones. The paper reviews the quality control issues in surface quality monitoring of big ground rolls where process vibrations (i.e. chatter) are one of major concerns. A multi-sensor approach for vibration onset detection, based on the use of a multi-channel implementation of the Principal Component Analysis, is proposed. The potential benefits, the implementation issues, and the main criticalities are discussed by analysing data of a real industrial application.
Thickness Optimization of Polyurethane Floor Insulation Based on Analysis of the Heat Transfer in a Multi-Layer
Authors: Moosavi Ali , Saidi Mohammad Hassan , Reshadi Milad
Published: October 2014

During the year, due to weather conditions, the temperature fluctuations at surface level cause problems in underground pipes as a result of freezing water. One of the best prevention strategies is the use of polyurethane floor insulation for keeping the temperature of clay above zero degrees Celsius. In this study to calculate the minimum thickness of polyurethane insulation layer, the differential equation of energy is solved based on principle of separation of variables using imaginary eigenvalues for consistency with the temperature distribution in multi-layer consist of asphalt, gravel and polyurethane with finite thickness and clay as a semi-infinite medium with periodic thermal boundary conditions at surface level. Numerical approach is performed in Matlab and the results show that by using a thin layer of polyurethane it’s possible to greatly reduce the insertion depth of water pipes.
Improvement of the Welding Inspection Process for Projects in the Oil and Gas Industry Using Six Sigma Methodology
Authors: Yousef Muhannad A. , Al-Omairi Khalid , Al-Shehri Abdul-Ilah , Kakpovbia Anthony E.
Published: October 2014

At the start of welding activities in oil and gas projects, high welding rejection rates (WRR) are often reported. This is a cause for concern to companies because welding defects that are not identified nor corrected can have serious consequences, such as on asset integrity, cost of rework, and schedule impact. Therefore, the quality organizations immediately investigate the different causes and recommend solutions which eventually contributes toward lowering the WRR.

Based on recent field studies conducted in oil and gas projects using the Six Sigma methodology, high WRRs are caused by many factors, including but not limited to the following:

1. New and inexperienced welders with poor welding techniques.

2. Poor environments surrounding the welding activities.

3. Discrepancies and inaccurate data in the welding tracking system (WTS).

These contributing factors can be reduced and eliminated by implementing a strong welding inspection and control program with the following recommendations:

1. Screen for qualified and experienced welders with a proven successful welding history before starting the welding.

2. Test the welders on-site before actual production welding.

3. Implement an encouragement scheme for welders by having frequent toolbox meetings and presenting awards for the best welders according to the lowest rejection rates.

4. Assess the WTS constantly to prevent any inaccurate data.
Oil Stiction in Fast Switching Annular Seat Valves for Digital Displacement Fluid Power Machines
Authors: Roemer Daniel B. , Johansen Per , Pedersen Henrik C. , Andersen Torben O.
Published: October 2014

Digital Displacement (DD) fluid power machines utilizes electronically controlled seat valves connected to pressure chambers to obtain variable displacement with high operational efficiency and high bandwidth. To achieve high efficiency, fast valve switching is essential and all aspects related to the dynamic behaviour of the seat valves must be considered to optimize the machine efficiency. A significant effect influencing the valves switching performance is the presence of oil stiction when separating the contact surfaces in valve opening movement. This oil stiction force is limited by cavitation for low pressure levels, e.g. valves connected to the low pressure manifold, however for valves operated at higher pressure levels, the oil stiction force is dominating when the separating surfaces are close to contact.

This paper presents an analytic solution to the oil stiction force for annular seat valves suitable for DD applications based on the Reynolds equation and considers contact surface curvature and attack angle. A dynamic cavitation zone is included in the stiction model, and cavitation is found to be present even for seat valves surrounded by high pressure levels.
Effect of Corrugation on the Performance of Porous Baffles Used as Weather Shelters on Oil and Gas Platforms
Authors: Polanco Geanette , Mustafa Mohamad Y. , Xu Yizhong
Published: October 2014

Porous baffles are usually used for weather protection on onshore and offshore oil installations in order to provide a sheltered area for personnel to operate. Corrugated fences are more favourable than flat fences in large installations, due to their increased stiffness; however, the performance of those fences is expected to differ from flat fences due to changes in porosity and flow structure. In this work, the experimental and numerical studies of the influence of corrugated fence on the flow characteristics are presented. The tri-dimensional effect imposed by the angle of corrugation and the depth of the fence influences the windward and leeward flow characteristics with respect to the fence. Velocity coefficient is used as one important parameter for measuring the performance of porous fences. It was found that, under similar conditions, the total obstruction produced by the corrugated fence varies significantly from that of the flat fence. Hence, velocity reduction for a corrugated fence system is expected to be smaller. A complete description of the physics of the fluid mechanics around the fence is given. Furthermore, the behaviour of the stream lines close to the fences in both cases; corrugated and non-corrugated, were studied using CFD techniques. Through observation of local pressure distribution, it was possible to reveal how velocity variations were concentrated around the inclined sections of the corrugated fence. In performing the numerical simulations, a two dimensional approach was initially implemented to capture the flow behaviour in the vicinity of the inclined sections. Subsequently, a tri-dimensional simulation on a section of the fence was undertaken and compared with experimental data. The results of the simulations were in good agreement with experimental data obtained from wind tunnel tests.
Virtual Academic Teaching for Next Generation Engineers
Authors: Fortuna Fabio , Bella Gino , Barbuto Mirko , Conti Riccardo , Cozzolino Raffaello , Di Francesco Silvia , Donno Alfredo , Duraccio Vincenzo , Giannini Oliviero , Montesarchio Valeria , Monti Alessio , Tribioli Laura , Trovalusci Federica
Published: October 2014

Recent advances in web technology have transformed the World-Wide-Web from delivering static text to providing an easily accessible multimedia channel for dynamic, interactive communication. By using such technologies, academic teaching may evolve toward the next-generation way to transfer knowledge. At present time, there are two approaches that can be found: the Massive Open Online Courses (MOOC) approach that delivers video interactive classes to the vast audience with an open-access philosophy and Restrict-Access Courses (RAC) that deliver classes and, more important, standard degrees to limited audience [1]. While the two approaches are comparable when dealing with most academic disciplines, teaching engineering has some peculiarities that let the restricted–access course a more viable solution.

First of all, engineering schools must prepare the student for the profession. In most countries, after the degree there is a professional practice period, thus a closer relation between teacher and students allows bringing the professional knowledge embedded in the academy.

Being also a scientific discipline, engineering takes advantage from a close contact between teaching and research, especially for cutting-edge technologies. Finally, student projects are one of the most important steps of the educational path of the young engineers. Good student projects need one to one supervision, an adequate environment in particular for lab practice, and campuses that only restricted-access academies may provide.
Fuzzy Model for Electrostatic Fluidized Bed Coating
Authors: Trovalusci Federica , Barletta Massimiliano , Giannini Oliviero
Published: October 2014

The study concerns the coating process of metal substrates in an electrostatic fluidized bed (EFB).

This eco-friendly process is profitably used to coat components of particularly complex shapes. Although this technology is widely spread in several industrial domains, the implementation of appropriate process control procedures is still object of investigation.

A model was generated from experimental data with the aim of predicting, for any set of process parameters, the resulting coating thickness of the sample. With a design of experiment (DOE) approach, the experimental investigation, that is the base for the model, quantifies the coating thickness as a function of the main process parameters namely coating time, applied voltage, and gas flow rate fed into the fluidized bed.

This study addresses the effect of the inherent uncertainties on the predicted coating thickness caused by the approximation in the model parameters. In particular, a fuzzy-logic based approach is used to describe the model uncertainties and the transformation method is used to propagate their effect on the thickness. The fuzzy results are then compared with the data produced by the experimentation leading to the evaluation of the membership level of the dataset to the uncertain model.
Static and Dynamic Handling Stability of Server Rack Computers
Authors: Notohardjono Budy D. , Sanders Robert
Published: October 2014

This paper discusses the static and dynamic stability analysis of rack or frame computer/server products during shipping and relocation. The static stability is the ability of server products to resist tipping over on a typical raised floor in a datacenter or when it is installed in its operational product environment. The dynamic stability is the ability to resist tipping over when a velocity change occurs during re-location either on flat or inclined planes. The product consists of a frame or a rack in which components such as processor units, input-output units and power supplies are installed.

The static stability analysis presented here calculates the tip over threshold angle, which is the maximum angle of an inclined plane on which the product can be placed without tipping over. The location of the installed components in a frame, the dimension and weight of the installed components, and the dimension of the product dictate the overall static stability of the product. Specifically, those parameters affect the location of the center of gravity of the product and the tip over threshold angle. The tip over threshold angle is a critical parameter influencing the dynamic stability of the product..

The dynamic stability of an unpackaged product moving on casters can be calculated using the conservation of mechanical energy principle. Finite element modeling is a good way to evaluate the dynamic stability of a product during manual handling or mechanical handling; for instance, on a forklift. The objective of the finite element modeling is to provide guidelines on the maximum speed, minimum radius curvature, and safe turning speed of a forklift when transporting a product.

The main objective of the analysis presented here is to provide a method for analyzing the static and dynamic stability of a rack style computer server product during shipping, relocation, and handling.
Two-Stroke Marine Diesel Engine Variable Injection Timing System Performance Evaluation and Optimum Setting for Minimum Fuel Consumption at Acceptable NOx Levels
Authors: Hountalas Dimitrios T. , Raptotasios Spiridon , Antonopoulos Antonis , Daniolos Stavros , Dolaptzis Iosif , Tsobanoglou Maria
Published: October 2014

Currently the most promising solution for marine propulsion is the two-stroke low-speed diesel engine. Start of Injection (SOI) is of significant importance for these engines due to its effect on firing pressure and specific fuel consumption. Therefore these engines are usually equipped with Variable Injection Timing (VIT) systems for variation of SOI with load. Proper operation of these systems is essential for both safe engine operation and performance since they are also used to control peak firing pressure.

However, it is rather difficult to evaluate the operation of VIT system and determine the required rack settings for a specific SOI angle without using experimental techniques, which are extremely expensive and time consuming. For this reason in the present work it is examined the use of on-board monitoring and diagnosis techniques to overcome this difficulty. The application is conducted on a commercial vessel equipped with a two-stroke engine from which cylinder pressure measurements were acquired. From the processing of measurements acquired at various operating conditions it is determined the relation between VIT rack position and start of injection angle. This is used to evaluate the VIT system condition and determine the required settings to achieve the desired SOI angle. After VIT system tuning, new measurements were acquired from the processing of which results were derived for various operating parameters, i.e. brake power, specific fuel consumption, heat release rate, start of combustion etc. From the comparative evaluation of results before and after VIT adjustment it is revealed an improvement of specific fuel consumption while firing pressure remains within limits. It is thus revealed that the proposed method has the potential to overcome the disadvantages of purely experimental trial and error methods and that its use can result to fuel saving with minimum effort and time.

To evaluate the corresponding effect on NOx emissions, as required by Marpol Annex-VI regulation a theoretical investigation is conducted using a multi-zone combustion model. Shop-test and NOx-file data are used to evaluate its ability to predict engine performance and NOx emissions before conducting the investigation. Moreover, the results derived from the on-board cylinder pressure measurements, after VIT system tuning, are used to evaluate the model’s ability to predict the effect of SOI variation on engine performance. Then the simulation model is applied to estimate the impact of SOI advance on NOx emissions. As revealed NOx emissions remain within limits despite the SOI variation (increase).
Human Powered Vehicle Design: A Challenge for Engineering Education
Authors: Baldissera Paolo , Delprete Cristiana
Published: October 2014

Student Team Challenges on specific topics are growing in popularity as efficient ways to stimulate students’ independent work, technical and management learning as well as socialization and internationalization. Many competitions are focused on ground vehicles (SAE Formula, Motostudent, Shell Eco Marathon, Solar Challenge), with different focuses on performance, fuel consumption or other depending on the aim of the event. An interesting approach is proposed in the United States by the ASME HPV Challenge, which is focused on Human Powered Vehicles. This class of vehicles allows not only to set-up a classical competition in terms of design, innovation, presentation, manufacturing and racing, but also to grow the student awareness about speed-energy relation. An HPV gives to the rider a direct feedback on a “human-scale” about energy quantities involved in personal mobility. The main returns by the use of this specific topic for a student challenge are: better understanding of the sustainable mobility problem, awareness about the potential and the limits of human muscular power, development of technical skills about design and engineering of lightweight and efficient vehicles, stimulation of the HPVs market development (the students are both potential future designers/manufacturers and/or customers), promotion of healthy and engaging physical activities. In this context, while Europe is rich of HPVs amateurs and manufacturers and is the usual location of the WHPVA World Championship, there is a lack of an educational framework involving students and teachers. Starting from the end of ZEV-HPV Erasmus Intensive Program 2011–2013, the proposal of creating a specific HPV challenge for the European students was developed by the authors. In particular, it was evaluated that by integrating the Student Challenge in the WHPVA World Championship as a special “Educational” category, many reciprocal advantages could be obtained: logistic and organizational support from the WHPVA and its national representatives, in particular for racing and timing, reciprocal technical and cultural exchange between students, academics and the hundred of amateur rider/designer/builder that were attending the event in the last decade, growth and renewal of the European HPVs community by aggregating young people around the subject and by stimulating the research of innovative solutions. After an in-depth analysis of the arguments reported above, an overview of the rules for the 1st edition of EU HPV Student Challenge will be presented and compared to analogous international competitions from an educational perspective.
Vibro-Acoustic Analysis of a Heavy Duty Truck Cabin
Authors: Yenerer Hakan , Stan Andrei Cristian , Sendur Polat , Basdogan Ipek
Published: October 2014

Automotive manufacturers invest a lot of effort and money to enhance the vibro-acoustic performance of their products. In a complex dynamic system such as a truck cabin, the enhancement effort may be very difficult and time-consuming if only the ‘trial and error’ method is used without prior knowledge about the noise contributors.

The purpose of this paper is to identify the most influential noise radiating panel in a passenger cabin compartment of a heavy duty truck. The noise inside the vehicle cabin originates from various sources and travels through many pathways. The first step of sound quality refinement is to find the pathways and corresponding operational internal forces. Operational acceleration responses and frequency response functions (FRFs) are measured on a prototype truck to determine the excitation forces while engine is running in operational conditions. Once these internal forces are identified using the experimental force identification (FI) technique, they are utilized to predict the total sound pressure level inside the cabin and also perform the panel acoustic contribution analysis (PACA) to determine the most problematic panel of the cabin. A coupled vibro-acoustic finite element model (FEM) is used to predict the sound pressure level inside the cabin. Sound pressure levels at the driver’s and passenger’s right and left ears are determined numerically for excitation coming from the cabin mounts ranging between 20–200 Hz. When the most noise radiating panel is identified, it can be redesigned to improve the sound pressure level inside the cabin.
Reciprocal Frame Optimisation for Laser-Tube Technology
Authors: Ruttico Pierpaolo , Lorusso Pasquale , Arrighi Stefano
Published: October 2014

The research project presented in this paper investigates the architectonic and constructive potential of computational design and digital fabrication in steel construction. The original contribution of this project is the development of a digital design system that solves reciprocal interlinked structures through algorithmic design and iterative processes. The system is implemented with parametric definitions that optimize the mass-customization process for laser tube technology. In order to validate the assumptions, a mock-up has been realized out of stainless steel elements. The tubes are cut by a laser-tube robotic system, then manually assembled.
Performance Evaluation for Cable Direct Driven Robot
Authors: Boschetti Giovanni , Trevisani Alberto
Published: October 2014

The evaluation of cable robot performances cannot neglect the considerable limitations introduced by cable tension bilateral bounds, i.e. the fact that neither negative nor limitless cable forces can be exerted. Therefore, such constraints must be explicitly accounted for and the indexes typically employed for parallel robots cannot be employed straightforwardly. In this work, instead of proposing a new performance index, we introduce an approach to performance evaluations which is based on the computation of the maximum force, along a specific direction, which can be exerted by the cables on the moving platform of a fully actuated or redundant cable robot. Such a computation, once extended to the whole workspace of a robot or, if needed, to any direction, openly and effectively describes the robot performances and can be extremely useful in practice. The application of the method to two fully actuated and fully constrained planar cable robots, together with a comparison with popular performance indexes, gives evidence of the method effectiveness.
Some Unexpected Results in the Stress Calculation Around Multiple Holes in an Isotropic Plate Under In-Plane-Loads
Authors: Asmar Ghazi H. , Chakar Elie A. , Jabbour Toni G.
Published: October 2014

The Schwarz alternating method, along with Muskhelishvili’s complex potential method, is used to calculate the stresses around non-intersecting circular holes in an infinite isotropic plate subjected to in-plane loads at infinity. The holes may have any size and may be disposed in any manner in the plate, and the loading may be in any direction.

Complex Fourier series, whose coefficients are calculated using numerical integration, are incorporated within a Mathematica program for the determination of the tangential stress around any of the holes. The stress values obtained are then compared to published results in the literature and to results obtained using the finite element method.

It is found that part of the results generated by the authors do not agree with some of the published ones, specifically, those pertaining to the locations and magnitudes of certain maximum stresses occurring around the contour of holes in a plate containing two holes at close proximity to each other. This is despite the fact that the results from the present authors’ procedure have been verified several times by finite element calculations.

The object of this paper is to present and discuss the results calculated using the authors’ method and to underline the discrepancy mentioned above.
Integrating focused ion beam–scanning electron microscope with confocal Raman microscope into a single instrument
Authors: Jiruše Jaroslav , Haničinec Martin , Havelka Miloslav , Hollricher Olaf , Ibach Wolfram , Spizig Peter
Published: October 2014

The authors have developed a new method to integrate a scanning electron microscope (SEM) with a confocal Raman microscope (CRM) that uses full optical microscopy inside the vacuum chamber of the SEM, and thus bring the capabilities of a stand-alone CRM instrument into the combined tool. A focused ion beam is also integrated into the system, thereby equipping a single instrument with electron, ion, and photon beams. Chemical imaging with the CRM is done by objective lens scanning. The confocal arrangement of the instrument is also capable of nondestructive three-dimensional Raman tomography on transparent samples.
Cdc48 and a ubiquitin ligase drive disassembly of the CMG helicase at the end of DNA replication
Authors: Maric Marija , Maculins Timurs , De Piccoli Giacomo , Labib Karim
Published: October 2014

How to stop after copying the genome

Replication is highly regulated: Failure to copy any part of the genome or copying parts of it more than once can cause genome instability with potentially disastrous consequences. Maric
et al.
and Priego Moreno
et al.
show that the DNA replication machinery, which stably encircles DNA during the duplication process, is actively disassembled once replication is complete (see the Perspective by Bell). The protein ring encircling the DNA is covalently modified, which allows it to be opened and the whole replication complex to be removed from DNA by a special disassembly complex.

Science
, this issue
10.1126/science.1253596
, p.
477
; see also p.
418
Coping with the curse of freshwater variability
Authors: Hall J. W. , Grey D. , Garrick D. , Fung F. , Brown C. , Dadson S. J. , Sadoff C. W.
Published: October 2014

Institutions, infrastructure, and information for adaptation
Paleoindian settlement of the high-altitude Peruvian Andes
Authors: Rademaker Kurt , Hodgins Gregory , Moore Katherine , Zarrillo Sonia , Miller Christopher , Bromley Gordon R. M. , Leach Peter , Reid David A. , Álvarez Willy Yépez , Sandweiss Daniel H.
Published: October 2014

Mountain dwellers of the Pleistocene

Humans colonized the inhospitable high Andes at least 11.5 thousand years ago. Rademaker
et al.
unearthed evidence of hunter-gatherer occupation at heights of almost 4500 m in Peru in two open-air sites. The sites contained more than 750 tools, including likely spearheads and scrapers. A nearby rockshelter with sooted ceilings and floor detritus may have been a campsite. The sites were probably used seasonally for hunting vicuña and other high-altitude prey.

Science
, this issue p.
466
Response to Comment on “A Jurassic ornithischian dinosaur from Siberia with both feathers and scales”
Authors: Godefroit Pascal , Sinitsa Sofia M. , Dhouailly Danielle , Bolotsky Yuri L. , Sizov Alexander V. , McNamara Maria E. , Benton Michael J. , Spagna Paul
Published: October 2014

Lingham-Soliar questions our interpretation of integumentary structures in the Middle-Late Jurassic ornithischian dinosaur
Kulindadromeus
as feather-like appendages and alternatively proposes that the compound structures observed around the humerus and femur of
Kulindadromeus
are support fibers associated with badly degraded scales. We consider this hypothesis highly unlikely because of the taphonomy and morphology of the preserved structures.
Unanchored ubiquitin in virus uncoating
Authors: Rajsbaum Ricardo , García-Sastre Adolfo
Published: October 2014

Components of a cellular degradation system are exploited by influenza virus during infection

[Also see Report by

Banerjee
et al.

]
Epic pre-Columbian voyage suggested by genes
Authors: Lawler Andrew
Published: October 2014

South American DNA found in Easter Islanders.
Searching for science in India's traditional medicine
Authors: Pulla Priyanka
Published: October 2014

Critics say ayurgenomics is at best a quixotic quest.
Draft Genome Assemblies of Proteus mirabilis ATCC 7002 and Proteus vulgaris ATCC 49132
Authors: Minogue T. D. , Daligault H. E. , Davenport K. W. , Bishop-Lilly K. A. , Bruce D. C. , Chain P. S. , Coyne S. R. , Chertkov O. , Freitas T. , Frey K. G. , Jaissle J. , Koroleva G. I. , Ladner J. T. , Palacios G. F. , Redden C. L. , Xu Y. , Johnson S. L.
Published: October 2014

The pleomorphic swarming bacilli of the genus
Proteus
are common human gut commensal organisms but also the causative agents of recurrent urinary tract infections and bacteremia. We sequenced and assembled the 3.99-Mbp genome of
Proteus mirabilis
ATCC 7002 (accession no. JOVJ00000000) and the 3.97-Mbp genome of
Proteus vulgaris
ATCC 49132 (accession no. JPIX00000000), both of which are commonly used reference strains.
Combination of an Unbiased Amplification Method and a Resequencing Microarray for Detecting and Genotyping Equine Arteritis Virus
Authors: Hans Aymeric , Gaudaire Delphine , Manuguerra Jean-Claude , Leon Albertine , Gessain Antoine , Laugier Claire , Berthet Nicolas , Zientara Stephan
Published: October 2014

This study shows that an unbiased amplification method applied to equine arteritis virus RNA significantly improves the sensitivity of the real-time reverse transcription-quantitative PCR (RT-qPCR) recommended by the World Organization for Animal Health. Twelve viral RNAs amplified using this method were hybridized on a high-density resequencing microarray for effective viral characterization.
Persistent Hepatitis C Virus Infection Impairs Ribavirin Antiviral Activity through Clathrin-Mediated Trafficking of Equilibrative Nucleoside Transporter 1
Authors: Panigrahi Rajesh , Chandra Partha K. , Ferraris Pauline , Kurt Ramazan , Song Kyoungsub , Garry Robert F. , Reiss Krzysztof , Coe Imogen R. , Furihata Tomomi , Balart Luis A. , Wu Tong , Dash Srikanta
Published: October 2014

Ribavirin (RBV) continues to be an important component of interferon-free hepatitis C treatment regimens, as RBV alone does not inhibit hepatitis C virus (HCV) replication effectively; the reason for this ineffectiveness has not been established. In this study, we investigated the RBV resistance mechanism using a persistently HCV-infected cell culture system. The antiviral activity of RBV against HCV was progressively impaired in the persistently infected culture, whereas interferon lambda 1 (IFN-λ1), a type III IFN, showed a strong antiviral response and induced viral clearance. We found that HCV replication in persistently infected cultures induces an autophagy response that impairs RBV uptake by preventing the expression of equilibrative nucleoside transporter 1 (ENT1). The Huh-7.5 cell line treated with an autophagy inducer, Torin 1, downregulated membrane expression of ENT1 and terminated RBV uptake. In contrast, the autophagy inhibitors hydroxychloroquine (HCQ), 3-methyladenine (3-MA), and bafilomycin A1 (BafA1) prevented ENT1 degradation and enhanced RBV antiviral activity. The HCV-induced autophagy response, as well as treatment with Torin 1, degrades clathrin heavy chain expression in a hepatoma cell line. Reduced expression of the clathrin heavy chain by HCV prevents ENT1 recycling to the plasma membrane and forces ENT1 to the lysosome for degradation. This study provides a potential mechanism for the impairment of RBV antiviral activity in persistently HCV-infected cell cultures and suggests that inhibition of the HCV-induced autophagy response could be used as a strategy for improving RBV antiviral activity against HCV infection.

IMPORTANCE
The results from this work will allow a review of the competing theories of antiviral therapy development in the field of HCV virology. Ribavirin (RBV) remains an important component of interferon-free hepatitis C treatment regimens. The reason why RBV alone does not inhibit HCV replication effectively has not been established. This study provides a potential mechanism for why RBV antiviral activity is impaired in persistently HCV-infected cell cultures and suggests that inhibition of the HCV-induced autophagy response could be used as a strategy to increase RBV antiviral activity against HCV infection. Therefore, it is anticipated that this work would generate a great deal of interest, not only among virologists but also among the general public.
The Sheep Tetherin Paralog oBST2B Blocks Envelope Glycoprotein Incorporation into Nascent Retroviral Virions
Authors: Murphy Lita , Varela Mariana , Desloire Sophie , Ftaich Najate , Murgia Claudio , Golder Matthew , Neil Stuart , Spencer Thomas E. , Wootton Sarah K. , Lavillette Dimitri , Terzian Christophe , Palmarini Massimo , Arnaud Frédérick
Published: October 2014

Bone marrow stromal cell antigen 2 (BST2) is a cellular restriction factor with a broad antiviral activity. In sheep, the
BST2
gene is duplicated into two paralogs termed
oBST2A
and
oBST2B
. oBST2A impedes viral exit of the Jaagsiekte sheep retroviruses (JSRV), most probably by retaining virions at the cell membrane, similar to the “tethering” mechanism exerted by human BST2. In this study, we provide evidence that unlike oBST2A, oBST2B is limited to the Golgi apparatus and disrupts JSRV envelope (Env) trafficking by sequestering it. In turn, oBST2B leads to a reduction in Env incorporation into viral particles, which ultimately results in the release of virions that are less infectious. Furthermore, the activity of oBST2B does not seem to be restricted to retroviruses, as it also acts on vesicular stomatitis virus glycoproteins. Therefore, we suggest that oBST2B exerts antiviral activity using a mechanism distinct from the classical tethering restriction observed for oBST2A.

IMPORTANCE
BST2 is a powerful cellular restriction factor against a wide range of enveloped viruses. Sheep possess two paralogs of the
BST2
gene called
oBST2A
and
oBST2B
. JSRV, the causative agent of a transmissible lung cancer of sheep, is known to be restricted by oBST2A. In this study, we show that unlike oBST2A, oBST2B impairs the normal cellular trafficking of JSRV envelope glycoproteins by sequestering them within the Golgi apparatus. We also show that oBST2B decreases the incorporation of envelope glycoprotein into JSRV viral particles, which in turn reduces virion infectivity. In conclusion, oBST2B exerts a novel antiviral activity that is distinct from those of BST2 proteins of other species.
The HIV-1 gp120 CD4-Bound Conformation Is Preferentially Targeted by Antibody-Dependent Cellular Cytotoxicity-Mediating Antibodies in Sera from HIV-1-Infected Individuals
Authors: Veillette Maxime , Coutu Mathieu , Richard Jonathan , Batraville Laurie-Anne , Dagher Olina , Bernard Nicole , Tremblay Cécile , Kaufmann Daniel E. , Roger Michel , Finzi Andrés
Published: October 2014

Recent studies have linked antibody Fc-mediated effector functions with protection or control of human immunodeficiency type 1 (HIV-1) and simian immunodeficiency (SIV) infections. Interestingly, the presence of antibodies with potent antibody-dependent cellular cytotoxicity (ADCC) activity in the Thai RV144 vaccine trial was suggested to correlate with decreased HIV-1 acquisition risk. These antibodies recently were found to recognize HIV envelope (Env) epitopes exposed upon Env-CD4 interaction. CD4 downregulation by Nef and Vpu, as well as Vpu-mediated BST-2 antagonism, were reported to modulate exposure of those CD4-induced HIV-1 Env epitopes and were proposed to play a role in reducing the susceptibility of infected cells to ADCC mediated by this class of antibodies. Here, we report the high prevalence of antibodies recognizing CD4-induced HIV-1 Env epitopes in sera from HIV-1-infected individuals, which correlated with their ability to mediate ADCC responses against HIV-1-infected cells, exposing these Env epitopes at the cell surface. Furthermore, our results indicate that Env variable regions V1, V2, V3, and V5 do not represent a major determinant for ADCC responses mediated by sera from HIV-1-infected individuals. Altogether, these findings suggest that HIV-1 tightly controls the exposure of certain Env epitopes at the surface of infected cells in order to prevent elimination by Fc-effector functions.

IMPORTANCEHere, we identified a particular conformation of HIV-1 Env that is specifically targeted by ADCC-mediating antibodies present in sera from HIV-1-infected individuals. This observation suggests that HIV-1 developed sophisticated mechanisms to minimize the exposure of these epitopes at the surface of infected cells.