Mechanical Engineering

We develop a multiscale simulation method for dense granular drainage, based on the recently proposed spot model, where the particle packing flows by local collective displacements in response to diffusing "spots" of interstitial free volume. By comparing with discrete-element method (DEM) simulations of 55,000 spheres in a rectangular silo, we show that the spot simulation is able to approximately capture many features of drainage, such as packing statistics, particle mixing, and flow profiles. The spot simulation runs two to three orders of magnitude faster than DEM, making it an appropriate method for real-time control or optimization. We demonstrate extensions for modeling particle heaping and avalanching at the free surface, and for simulating the boundary layers of slower flow near walls. We show that the spot simulations are robust and flexible, by demonstrating that they can be used in both event-driven and fixed timestep approaches, and showing that the elastic relaxation step used in the model can be applied much less frequently and still create good results.

Thermodynamic analysis methods, based on an exergy metric, have been developed to improve system efficiency of traditional heat driven systems such as ground based power plants and aircraft propulsion systems. However, in more recent years interest in the topic has broadened to include applying these second law methods to the field of aerodynamics and complete aerospace vehicles. Work to date is based on highly simplified structures, but such a method could be shown to have benefit to the highly conservative and risk averse commercial aerospace sector. This review justifies how thermodynamic exergy analysis has the potential to facilitate a breakthrough in the optimization of aerospace vehicles based on a system of energy systems, through studying the exergy-based multidisciplinary design of future flight vehicles.

Lattice materials can be designed through their microstructure while concurrently considering fabrication feasibility. Here, we propose two types of composite lattice materials with enhanced resistance to buckling: (a) hollow lattice materials fabricated by a newly developed bottom-up assembly technique and the previously developed thermal expansion molding technique and (b) hierarchical lattice materials with foam core sandwich trusses fabricated by interlocking assembly process. The mechanical performance of sandwich structures featuring the two types of lattice cores was tested and analyzed theoretically. For hollow lattice core material, samples from two different fabrication processes were compared and both failed by nodal rupture or debonding. In contrast, hierarchical lattice structures failed by shear buckling without interfacial failure in the sandwich struts. Calculations using established analytical models indicated that the shear strength of hollow lattice cores could be...

A new mechanism of fracture toughness enhancement in nanocrystalline metals and ceramics is suggested. The mechanism represents the cooperative grain boundary (GB) sliding and stress-driven GB migration process near the tips of growing cracks. It is shown that this mechanism can increase the critical stress intensity factor for crack growth in nanocrystalline materials by a factor of three or more and thus considerably enhances the fracture toughness of such materials.

This work involves the determination of transport coefficients and equation of state of supercritical fluids by molecular dynamics (MD) simulations on parallel computers using the Green-Kubo formulae and the virial equation of state, respectively. The MD program uses an effective Lennard-Jones potential, linked cell lists for efficient sorting of molecules, periodic boundary conditions, and a modified velocity Verlet algorithm for particle displacement. Previously, simulations had been carried out on pure argon, nitrogen and oxygen, and this has now been extended to ethylene, C^H^, at various supercritical conditions, with shear viscosity and thermal conductivity coefficients, and pressures computed for most of the conditions. The results compare well with experimental and National Institute of Standards and Technology (NIST) values.

A previously synthesized hyperbranched poly(butylene adipate) (HPBA) polymer was compared with a commercial dendritic polyol (HPOH) as a toughening agent for a commercial one-part epoxy resin. Both modifiers were added in weight percentages of 1, 3, 5, and 10%. The modified epoxies were characterized using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), melt rheological tests, and linear elastic fracture mechanics. Blend morphology and matrix-modifier interactions were evaluated using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis, respectively. The toughness-improvement effect was achieved without substantial impairment of thermomechanical properties or degradation of the thermal stability of the epoxy resin. A meaningful decrease in viscosity was achieved with both modifiers, contributing to an easier infusion processability. No evidence of new chemical linking was found although phase separation was observed by SEM, leading to the conclusion that only interfacial linkage occurs between modifiers and epoxy chains. SEM analysis also clearly shows the fracture mode changing from brittle to ductile by addition of modifiers, which was more evident for blends of HPBA.

Today, renewable energy sourcese.g. forest biomassare of great importance, not only domestic but also industrialf.i. wood fired power stationutilization is wide spread as well. However, the comminution of such fibrous texture materials requires relatively high energy and special grinding stress. In the thermal power station of AES Co. Ltd., Berente mainly wood biomass is burned as fuel. The size reduction of biomass is achieved by beater wheel mills, which were designed originally for coal. The aim of the research carried out by the University of Miskolc was to increase the capacity of the fuel supplying system. Systematic industrial and laboratory experimental series were carried out under different conditions and results are presented in this study. During the on-site industrial tests four fuel supplying systems (beater wheel mill, air classifier, heat exchanger, pipes) were equipped with a complete data acquisition system containing different sensors. Three sampling points were built 1) from the feed, 2) from the rejected coarse material after the air classifier and 3) from the final product (isokinetic) from the pneumatic transport pipe. Biomass moisture significantly influenced comminution energy consumption, especially for finer size reduction.

This article presents a new format of tool path polynomial interpolation in 5-axis machining. The linear interpolation usually used produces tangency discontinuities along the tool path, sources of decelerations of the machine tool whereas polynomial interpolation reduces the appearance of such discontinuities. The new format involves a faster tool path and a better surface quality. However, it imposes a modification of the process so as to take the interpolation format and the inverse kinematics transformation (necessary to 5-axis machining) into account. This article deals with the geometrical problem of tool path calculation. Validation tests are detailed. They show that profits concern the reduction of machining time as well as the quality of the machined surfaces. Indeed, the trajectory continuity avoids the appearance of marks and facets. q

In high-strength steels it is often difficult to distinguish between hydrogen embrittlement and various other brittle failure mechanisms. The objective of this work was to develop a sensitive analytical procedure based on secondary ion mass spectrometry (SIMS) that would allow in-service identification of local hydrogen accumulation, either during quality control or during failure analysis of electroplated items. Dynamic SIMS was found useful in identifying when baking of Cd-plated AISI 4340 steel was not carried out, thus potentially leading to hydrogen embrittlement. In all non-baked samples, an increase in the hydrogen signal was found at the Cd/steel interface. In baked samples, either a peak was not observed at the interface, or it was insignificant based on determination of the ratios between the hydrogen signals in the coating, interface and substrate. This reproducible effect was monitored even after 16 months storage in a desiccator. These observations make the procedure practical in suggesting more accurate, reliable and cost effective recommendations for prevention of failures. The main effect of baking was found to be effusion of hydrogen from the interface and the substrate steel into the atmosphere. A mechanism for delayed failure is suggested.

In the paper there is presented a dynamic model of the articulated shaft. The model is used for the analysis of critical angular velocities. This model can be rewritten into a computer program to handle rotating parts of gear pumps. Using the knowledge of the custom frequencies of the rotating parts one can prevent operational malfunctions of the pumps. The problems described in the contribution will serve as a basis for the formulation of critical speed of the gear pumps within the Program for Support of Applied Research and Experimental Development ALFA TA04010579 of the Technology Agency of the Czech Republic. Key words: articulated shaft, critical angular speed, geer pump

V článku je prezentován dynamický model kloubového hřídele, který je využíván pro analýzu kritických úhlových rychlostí. Tento model může být přepsán do počítačového programu, pro řešení rotujících částí zubových čerpadel. Využití znalosti vlastních frekvencí rotujících částí může zabránit provozním poruchám čerpadel.
Problematika popsaná v příspěvku bude sloužit jako východisko při formulaci modelu kritických otáček zubových čerpadel v rámci Programu na podporu aplikovaného výzkumu a experimentálního vývoje ALFA TA04010579 Technologické agentury České republiky.
Klíčová slova: kloubový hřídel, kritická úhlová rychlost, zubové čerpadlo

https://www.ijert.org/computer-aided-exhaust-valve-design-automation-using-creo-and-microsoft-excel-spreadsheet

https://www.ijert.org/research/computer-aided-exhaust-valve-design-automation-using-creo-and-microsoft-excel-spreadsheet-IJERTV9IS080211.pdf

3D Modeling has been widely used because of their ease in understanding, visualization, and generation of manufacturing drawing compared to 2D drafting. However modeling process is a time consuming and many draftsmen do not have the skills of performing such task. Exhaust valve is one of the component reputedly required nearly in all ic engines. It is the nose of the combustion engine to return exhaust gases out at a time of exhaust stroke. There are many tools and computer languages like C, C++, Python, Visual basic, Go language etc useful for task automation. In this paper we are automate the designing and solid modeling task of exhaust valve by creating graphical user tool to take input parameters required for exhaust valve design using visual basic programming language into the excel spreadsheet and integrate this spreadsheet with Creo or Pro-Engineering parametric tool for 3D solid modeling automation. To demonstrate our study we are considered to automate the exhaust valve design and solid model generation made by authors S.S Gawale & Dr S.N Shelke(8).

Silica-potash-lime stained-glasses from medieval age in Northern Europe are found in a poor conserv ation state. Their mechanisms of atmospheric corrosion are still not fully understood and need deeper investigation. A multi-scale analysis of K-Ca rich silicate glasses (ancient and model glass), showed modified layers characterised by a multilayer sequence consisting in the repetition of nm-thick laminae with different compositions. Crystalline phases (sulphates, carbonates and phos phates) are observed. The formation of these sequences is due chiefly to interdiffusion, followed by local dissolution pheno mena. Precipitation of secondary phases is enhanced by the presence of fractures, which facilitate fluid circulation.

A method for systematic reactor design, described by Hillestad , is applied to the Fischer-Tropsch synthesis. The reactor path is sectioned into stages and design functions are optimized to maximize an objective function. Two different objective functions are considered: the yield of wax and a measure of the profitability.

Adhesive bonding technique is used successfully for joining the carbon fibre reinforced plastics to metals or composite structures. A good design of adhesive joint with either simple or more complex geometry requires its stress and deformation states to be known for different boundary conditions. In case the adhesive joint is subjected to thermal loads, the thermal and mechanical mismatches of the adhesive and adherends cause thermal stresses. The plate-end conditions may also result in the adhesive joint to undergo large displacements and rotations whereas the adhesive and adherends deform elastically (small strain). In this study, the thermal and geometrically non-linear stress analyses of an adhesively bonded composite tee joint with single support plus an angled reinforcement made of unidirectional CFRPs were carried out using the non-linear finite element method. In the stress analysis, the effects of the large displacements were considered using the small displacement -large displacement theory. The stress states in the plates and the adhesive layer of the tee joint configurations bonded to a rigid base and a composite plate were investigated. An initial uniform temperature distribution was attributed to the adhesive joint for a stress free state, and then variable thermal boundary conditions, i.e. air flows with different velocity and temperature were specified along the outer surfaces of the tee joints. The thermal analysis showed that a non-uniform temperature distribution occurred in the tee joints, and high heat fluxes took place along the free surfaces of the adhesive fillets at the adhesive free ends. Later, the geometrical non-linear thermal-stress analysis of the tee joint was carried out for the final temperature distribution and two edge conditions applied to the edges of the vertical and horizontal plates (HP). High stress concentrations occurred around the rounded adherend corners inside the adhesive fillets at the adhesive free ends, and along the adhesive -composite adherend interfaces due to their thermal -mechanical mismatches. The most critical joint regions were adhesive fillets subjected to high thermal gradients, the middle region of HP, the region of the vertical plate corresponding to the free end of the vertical adhesive layer -left support interface. In addition, the support length had a small effect of reducing the peak stresses at the critical adherend and adhesive locations. q

International standards highlight the steps required by risk assessment and involving first hazard identification, then risk evaluation and finally, if necessary, risk assessment. To check approach appropriateness to "risk evaluation" from manual patient handling through MAPO, a cross study was carried out in view of checking relationship between this new risk assessment model and occurrence of acute low back pain. After proper training the MAPO screening method was assessed in 31 wards, 411 exposed subjects of geriatric hospitals. At the same time health data were collected on occurrence of low back pain episodes during the last year both in the exposed subjects' group and the external reference group (n�237). Risk and clinical assessment data were tutored and checked by EPM research unit. The logistic analysis was used as a method to evaluate the relationship between risk index and acute low back pain. Investigating relationship between acute low back pain episodes a...

A new method of designing nonimaging concentrators is presented and two new types of concentrators are developed. The first is an aspheric lens, and the second is a lens-mirror combination. A ray tracing of three-dimensional concentrators (with rotational symmetry) is also done, showing that the lens-mirror combination has a total transmission as high as that of the full compound parabolic concentrators, while their depth is much smaller than the classical parabolic mirror-nonimaging concentrator combinations. Another important feature of this concentrator is that the optically active surfaces are not in contact with the receiver, as occurs in other nonimaging concentrators in which the rim of the mirror coincides with the rim of the receiver.

Rainscreen wall design is still at its infancy stage even after its introduction about four decades ago. Research continues in an effort to set out appropriate design guidelines for rainscreen walls. This paper presents the key results of yearlong full-scale measurements of wind loading on rainscreen walls. The objective of this study is to estimate the impact of various design parameters on the wind loading on rainscreen. This paper also presents the current status of the available codes and standards regarding the wind loads on rainscreen walls and compares the full-scale results with some available provisions. r

Frequency modulation (FM) spectroscopy is a new method of optical heterodyne spectroscopy capable of sensitive and rapid measurement of the absorption or dispersion associated with narrow spectral features. The absorption or dispersion is measured by detecting the heterodyne beat signal that occurs when the FM optical spectrum of the probe wave is distorted by the spectral feature of interest. A short historical perspective and survey of the FM spectroscopy work performed to date is presented. Expressions describing the nature of the beat signal are derived. Theoretical lineshapes for a variety of experimental conditions are given. A signal-to-noise analysis is carried out to determine the ultimate sensitivity limits.

This research presents a new intelligent fault diagnosis and condition monitoring system for classification of different conditions of mechanical equipment that produces distinct thermal signatures for different fault conditions. This will be illustrated by considering the classification of six types of cooling radiator conditions: radiator tubes blockage, radiator fins blockage, loose connection between fins and tubes, radiator door failure, coolant leakage, and normal conditions. The proposed system consists of several distinct procedures including thermal image acquisition, image preprocessing, image processing, twodimensional discrete wavelet transform (2D-DWT), feature extraction, feature selection using a genetic algorithm (GA), and finally classification by artificial neural networks (ANNs). The 2D-DWT is implemented to decompose the thermal images. Subsequently, statistical texture features are extracted from the original images and are decomposed into thermal images. The significant selected features are used to enhance the performance of the designed ANN classifier for the 6 types of cooling radiator conditions (output layer) in the next stage. For the tested system, the input layer consisted of 16 neurons based on the feature selection operation. The best performance of ANN was obtained with a 16-6-6 topology. The classification results demonstrated that this system can be employed satisfactorily as an intelligent condition monitoring and fault diagnosis for a class of cooling radiator.

A new kinetic model for the fluid catalytic cracking (FCC) riser is developed. An elementary reaction scheme, for the FCC, based on cracking of a large number of lumps in the form of narrow boiling pseudocomponents is proposed. The kinetic parameters are estimated using a semi-empirical approach based on normal probability distribution. The correlation proposed for the kinetic parameters' estimation contains four parameters that depend on the feed characteristics, catalyst activity, and coke forming tendency of the feed. This approach eliminates the need of determining a large number of rate constants required for conventional lumped models. The model seems to be more versatile than existing models and opens up a new dimension for making generic models suitable for the analysis and control studies of FCC units. The model also incorporates catalyst deactivation and two-phase flow in the riser reactor. Predictions of the model compare well with the yield pattern of industrial scale plant data reported in literature. ᭧

The objective of this paper is to model and optimise solar organic rankine cycle (ORC) engines for reverse osmosis (RO) desalination using currently available solar thermal collectors. The proposed systems are intended to be potentially attractive for remote areas without (or with very high cost) access to the public electricity grid.

The goal of this paper is the development of control algorithms for the management of an automated warehouse system. As usual, the implementation of a control algorithm requires three preliminary steps: development of a reliable model; design of control procedures according to some optimality criteria; validation of these control procedures. As for modelling, a new level in the control architecture, namely an optimizer system, is introduced which performs real-time optimization thus simplifying the low-level control and improving the overall performance. In this context, the role of a detailed model of the whole warehouse is discussed and such a model is built up by using the colored timed Petri nets framework. As for control, we propose two control algorithms, derived under the simplifying continuity assumption of the rack locations, to optimize the operations of the cranes (moving within the aisles of the warehouse) and the operations of the shuttle (moving on a straight line placed between the aisles and the picking/refilling area), respectively. To evaluate the performance of the proposed control algorithms we define three different cost indices. As for the validation, extensive simulations are performed on the model in order to prove the effectiveness of the proposed control algorithms. A further validation of the algorithms has been performed on a test bed in order to take into account communication delays and computation times. Finally, the proposed architecture and control algorithms have been applied to a real plant. r

The paper presents the application of ultrasonic guided waves for fatigue crack detection in metallic structures. The study involves a simple fatigue test performed to introduce a crack into an aluminium plate. Lamb waves generated by a low-profile, surface-bonded piezoceramic transducer are sensed using a tri-axis, multi-position scanning laser vibrometer. The results demonstrate the potential of laser vibrometry for simple, rapid and robust detection of fatigue cracks in metallic structures. The method could be used in quality inspection and in-service maintenance of metallic structures in aerospace, civil and mechanical engineering industries.

ABSTRACT Lean Six Sigma Executive Overview (Case Study) Templates are a guide to Lean Six Sigma Green Belt, Lean Six Sigma Black Belt, and Lean Six Sigma Master Black Belt Projects. Lean Six Sigma Practitioners use the DMAIC (Define, Measure, Analyze, Improve, and Control) Phases. The Lean Six Sigma Executive Overview (Case Study) include the most common tools used in the DMAIC Phases. There are Backup Slides that include the tools and templates of Optional or less often tools. There are guidelines in the notes section. These templates are used to document Lean Six Sigma Projects as they are executed. I wish you well on your projects. Steven Bonacorsi, Lean Six Sigma Master Black Belt.

With the anticipated widespread usage of metal matrix composites (MMCs) in the near future, the machinability of high performance MMCs needs to be understood. This paper reports research results obtained from the grinding of aluminum-based MMCs reinforced with Al 2 O 3 particles using grinding wheels having SiC in a vitri®ed matrix and diamond in a resin-bonded matrix. The issues discussed are surface roughness, grinding force, type and size of the abrasives, grinding conditions, and the consequential sub-surface integrity. The study used grinding speeds of 1100±2200 m/min, a grinding depth of 15 mm for rough grinding and 1 mm for ®ne grinding, and cross-feeds of 3 and 1 mm for rough and ®ne grinding respectively, while maintaining a constant table feed-rate of 20.8 m/min. The surface integrity of the ground surfaces and sub-surfaces were analyzed using a scanning electron microscope (SEM) and a pro®lometer. The surface ®nish values, R a , were scattered in the range 0.15±0.70 mm for the rough-ground samples, whilst a narrower range of 0.20±0.35 mm was achieved for the ®ne-ground samples. Smearing of aluminum on the ground surfaces was seen for rough grinding, but was negligible for ®ne grinding because all the Al 2 O 3 particles of the ground surfaces were clearly visible when observed with the SEM. Grinding using a 3000-grit diamond wheel at depth of cut of 1 mm produced many ductile streaks on the Al 2 O 3 particles. Both the Al 2 O 3 particles and aluminum matrix were removed by micro machining. There were no cracks and defects found on the ground surfaces. There was almost no sub-surface damage, except for a rare cracked particle being found. Rough grinding with a SiC wheel followed by ®ne grinding with a ®ne-grit diamond wheel is recommended for the grinding of alumina/aluminum composites. # 2002 Published by Elsevier Science B.V.

Technological innovation in all areas has led to the appearance in recent years of new metallic and pearlescent materials, yet no exhaustive studies have been conducted to assess their colorimetric capabilities. The chromatic variability of these special-effect pigments may largely be due to the three-dimensional effect of their curved shapes and orientations when they are directionally or diffusely illuminated. Our study examines goniochromatic colors using the optimal colors (MacAdam limits) associated with normal colors (photometric scale of relative spectral reflectance from 0 to 1) under certain conventional illuminants and other light sources. From a database of 91 metallic and interference samples and using a multigonio-spectrophotometer, we analyzed samples with lightness values of more than 100 and others with lightness values of less than 100, but with higher chromaticities than optimal colors, which places them beyond the MacAdam limits. Our study thus demonstrates the existence of chromatic perceptions beyond the normal solid color associated with these materials and independent of the light source. The challenge for future research, therefore, is to replicate and render these color appearances in current and future color reproduction technologies for computer graphics.

Laser welding will be  an important welding process for different applications in aerospace , aircraft , automotive, electronics  and other industries, due to its capabilities like minimum heat affected zone, welding of various thicknesses, adoptability to welding of various materials possessing widely varying physical properties like melting point, absorption, reflectivity etc. It utilizes laser source as a non contact heat generation technology to weld different materials so as to achieve welds of high quality narrow width and high penetration depths without the need of filler wires. It may be necessary to understand the effect of process parameters on the weldability of materials for successful welding. Laser welding popularly uses two types of lasers like CO2 and Nd:YAG (neodymium doped yttrium – aluminium – garnet)  with different powers. Nd:YAG lasers are used to weld materials of different thicknesses involving powers upto 5 kW. Whereas, CO2 lasers are used for applications which involve higher powers upto 20 kW. Laser welding allows a direct transition from light energy into heat energy. This technique is involved with the process of laser - matter interaction in which various parameters such as pulse energy, pulse duration, spot size, welding speed, laser power, weld width, penetration depth, reflectivity, absorption coefficient, thermodynamic properties etc. are used for analysis. This paper presents a review of the different parameters including process as well as materials on the weldability of various materials like carbon steels, stainless steels, magnesium alloys, aluminium alloys, refractory materials such as vanadium, titanium, zirconium, tantalum etc. The selection of appropriate parameter for welding of specified material is discussed. The prominent weld defects common to the laser welding such as porosity, oxide inclusions, cracking, loss of alloying elements etc., are discussed as related to the microstructure as well as mechanical properties such as hardness, tensile strength and fatigue strength etc.

Feature extraction and dimensionality reduction are important tasks in many fields of science dealing with signal processing and analysis. The relevance of these techniques is increasing as current sensory devices are developed with ever higher resolution, and problems involving multimodal data sources become more common. A plethora of feature extraction methods are available in the literature collectively grouped under the field of Multivariate Analysis (MVA). This paper provides a uniform treatment of several methods: Principal Component Analysis (PCA), Partial Least Squares (PLS), Canonical Correlation Analysis (CCA) and Orthonormalized PLS (OPLS), as well as their non-linear extensions derived by means of the theory of reproducing kernel Hilbert spaces. We also review their connections to other methods for classification and statistical dependence estimation, and introduce some recent developments to deal with the extreme cases of large-scale and low-sized problems. To illustrate the wide applicability of these methods in both classification and regression problems, we analyze their performance in a benchmark of publicly available data sets, and pay special attention to specific real applications involving audio processing for music genre prediction and hyperspectral satellite images for Earth and climate monitoring.

Direct foaming of colloidal suspensions is a simple and versatile approach for the fabrication of macroporous ceramic materials. Wet foams produced by this method can be stabilized by longchain surfactants or by colloidal particles. In this work, we investigate the processing of particle-stabilized wet foams into crack-free macroporous ceramics. The processing steps are discussed with particular emphasis on the consolidation and drying process of wet foams. Macroporous alumina ceramics prepared using different consolidation and drying methods are compared in terms of their final microstructure, porosity, and compressive strength. Consolidation of the wet foam by particle coagulation before drying resulted in porous alumina with a closed-cell structure, a porosity of 86.5%, an average cell size of 35 lm, and a remarkable compressive strength of 16.3 MPa. On the other hand, wet foams consolidated via gelation of the liquid within the foam lamella led to porous structures with interconnected cells in the size range from 100 to 150 lm. The tailored microstructure and high mechanical strength of the macroporous ceramics can be of interest for the manufacture of bio-scaffolds, thermal insulators, impact absorbers, separation membranes, and light weight ceramics.

A model for predicting the refractive index of sodium iodide (NaI) aqueous solution n N I as a function of temperature T, NaI concentration c and wavelength was determined for moderate parameter variations. The equation accurately predicted the salt concentration required to match n N I to the refractive index of Pyrex n P .

The US National Aeronautics and Space Administration (NASA) Planetary Protection Office, in the Science Mission Directorate, has a long-term initiative under way in communication research and planning. The possibility of extraterrestrial life and efforts to search for evidence of it is one of NASAÕs key missions and a subject of great interest to the public. Planetary protection plays a key role in the search for signs of life elsewhere, and NASAÕs Planetary Protection Office has long recognized the importance of communications in accomplishing its goals and objectives. With solar system exploration missions advancing into the era of sample return and with the science of astrobiology changing assumptions about the nature and boundaries of life, the NASA Planetary Protection Office is expanding its communication research efforts. For the past decade, communication research sponsored by the NASA planetary protection program has focused on reaching members of the science community and addressing legal and ethical concerns. In 2003, the program broadened its communication research efforts, initiating the development of a communication strategy based on an interactive model and intended to address the needs of a broad range of external audiences. The NASA Planetary Protection Office aims to ensure that its scientific, bureaucratic, and other constituencies are fully informed about planetary protection policies and procedures and that scientists and officials involved in planetary protection are prepared to communicate with a variety of public audiences about issues relating to planetary protection. This paper describes NASAÕs ongoing planetary protection communication research, including development of a communication strategy and a risk communication plan.

The aim of the present study was to examine an adapted integrated psycho-social model to predict sport injury rehabilitation adherence. A longitudinal prospective design was used whereby 70 patients attending private physiotherapy clinics completed a battery of questionnaires both pre- and post-rehabilitation treatment based on the adapted framework. All participants were receiving treatment for tendonitis-related injuries. Adherence was monitored prospectively over the entire rehabilitation program using an observational measure of clinic adherence, a self-report measure of home-based adherence, in addition to monitoring attendance at rehabilitation sessions. In the initial phase of rehabilitation learning goal orientation, attitudes and perceived severity were found to predict rehabilitation intention. Intentions were also found to mediate the relationship between the aforementioned variables and clinic rehabilitation. Self-efficacy and self-motivation were predictors of clinic rehabilitation and attendance but not home rehabilitation. During the maintenance phase of rehabilitation coping ability and social support were predictors regarding all three measures of adherence. Implications for practitioners rehabilitating injured athletes are discussed.

Passive thermography is a non-contact monitoring approach with a great potential to be used for early bearing fault detection. However, to date, it has only been used to complement vibration-based approaches. However, the vibration-based methods are effective only in detecting physical damages such as bearing cracks and spalls. They cannot be easily used to monitor other unwanted conditions including the lack of lubrication. As such, this paper proposes a method based on temperature rise differences for the detection of both physical bearing damages and lubrication problems based on the mechanisms of the heat sources generated during a bearing operation as well as the mutual effects between these sources and bearing faults. The performance of the proposed method has been examined experimentally. The results have shown that the proposed method has a promising potential to be used for the detection of both physical bearing damages and lubrication related problems.

Digital image correlation (DIC) is assessed as a tool for measuring strains with high spatial resolution in woven-fiber ceramic matrix composites. Using results of mechanical tests on aluminum alloy specimens in various geometric configurations, guidelines are provided for selecting DIC test parameters to maximize the extent of correlation and to minimize errors in displacements and strains. The latter error is shown to be exacerbated by the presence of strain gradients. In a case study, the resulting guidelines are applied to the measurement of strain fields in a SiC/SiC composite comprising 2-D woven fiber. Sub-fiber tow resolution of strain and low strain error are achieved. The fiber weave architecture is seen to exert a significant influence over strain heterogeneity within the composite. Moreover, strain concentrations at tow crossovers lead to the formation of macroscopic cracks in adjacent longitudinal tows. Such cracks initially grow stably, subject to increasing app lied stress, but ultimately lead to composite rupture. Once cracking is evident, the composite response is couched in terms of displacements, since the computed strains lack physical meaning in the vicinity of cracks. DIC is used to identify the locations of these cracks (via displacement discontinuities) and to measure the crack opening displacement profiles as a function of applied stress.

The microbiota of two traditional Iranian cheeses (Lighvan and Koozeh) made of raw ewe's milk or mixtures of ewe's and goat's milk without starter addition was explored by culture-independent and culture-dependent approaches. Three batches of Lighvan and one of Koozeh were subjected to culture-independent polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) analysis and sequencing of dominant bands to assess the microbial structure and dynamics through manufacturing and ripening. In addition, culturing in elective media for lactic acid bacteria (M17, MRS and KAA), isolation of single colonies (n=130), molecular identification by PCR-amplified ribosomal DNA restriction analysis and sequencing, and differentiation at the strain level by repetitive extragenic palindromic PCR was also performed. DGGE analysis showed that the dominant amplicons in all four cheese batches belonged to Lactococcus lactis and Streptococcus parauberis. In addition, Escherichia coli and Lactococcus garvieae were frequently identified in both Lighvan and Koozeh, while Streptococcus

One of the most important issues in aircraft noise monitoring systems is the correct detection and marking of aircraft sound events through their measurement profiles, as this influences the reported results. In the recent ISO 20906 (unattended monitoring of aircraft sound in the vicinity of airports) this marking task is split into: detection from the sound level time history, classification of probable aircraft sound events, and the concluding identification of aircraft sound events through non-acoustic features.

This project is modeled around reducing the overall drag and lift coefficient by modifying the geometry and comprehending the underlying rootphenomenon for the variation in these drag values. The designing of models used in this project is done through SOLIDWORKS, and CFD simulation in FLUENT (ANSYS) respectively. The purpose of this project is to reduce the inefficiency caused due to aerodynamic factors of drag, lift by presenting development, design and optimization of the geometry modifications of the base model. The improvement of aerodynamic behaviour around the periphery of the model is investigated through numerical simulation. The Ahmed Reference Body having 10 degree rear slant angle has been taken as benchmark model in this paper. Simulation of variants of multifarious modifications and examination of their results is performed to find the best suited variant form (dimension) to boost the aerodynamic efficiency of the model. CFD simulations on Ahmed Body were carried out in order to serve as a benchmark for validating all the simulation results. The steady-state simulations are based on the Reynolds averaged Navier-Stokes equations, with turbulence closure provided through two-equation k-epsilon realizable models.

The automotive industry extensively uses elastomers as sealing systems in glass runner, shock absorbers, gaskets and several others. The challenges in the simulation of elastomers are non-linearity in material, geometry, boundary conditions and contact definition. The glass runners are the beadings around the door sash of an automobile. They ensure free movement of glass, prevention of leakage and vibration control.

Coordinate metrology is a field of metrology that is becoming increasingly popular in the manufacturing industry. Coordinate metrology enables the three-dimensional measurement to be carried out on complex object in a single setup. The instrument used for this purpose is known as the coordinate measuring machine or CMM. In general, the CMM comprises three frames that move along three orthogonal axes, i.e. X-, Y-and Z-axis. Usually, a contact device known as measuring probe is attached to the end of the Z-axis. The displacement along each axis is measured by a linear measurement system and the readings are sent to an electronic controller. The electronic controller is connected to a computer that also enables various types of data processing to be performed. Repeated measurements on similar objects can be done easily by programming the motion of the axes of the machine. This reduces the time taken for measurement and inspection up to 80% to 90%. These machines are made in various sizes and the methods of operation are based on either manual or computer-aided. 7.2. Types of CMM The basic CMM consists of three axes, each provided with a guide way that enable precise movement along a straight line. Each guide way has a carrier that moves along. The carrier enables the second carrier to move along a straight line based on the first guide way. Each axis is fitted with a precision scale that records the position of the carrier measured from a reference point. The measuring probe is fitted to the carrier on the third axis. When the measuring probe touches the object being measured, the measurement system records the position of all three axes. There are several physical configurations of CMMs. All the configurations have a method of moving the probe along three axes relative to the object. Although there are many designs of CMMs but they can be grouped into five basic types as follows: (a) Cantilever type, (b) Bridge type, (c) Horizontal arm type, (d) Column type and (e) Gantry type 7.2.1 Cantilever type CMM The schematic diagram of the cantilever type CMM is shown in Figure 6.1. In the cantilever type CMM the measuring probe it attached to the Z-axis and moves in the vertical direction. The Z-axis carrier is fitted to the cantilever arm and provides movement in the Y-direction. The Z-axis movement is provided by the table. This type of CMM design provides easy access to the work area and has high workspace volume.

Extrusion-based bioprinting (EBB) is a rapidly growing technology that has made substantial progress during the last decade. It has great versatility in printing various biologics, including cells, tissues, tissue constructs, organ modules and microfluidic devices, in applications from basic research and pharmaceutics to clinics. Despite the great benefits and flexibility in printing a wide range of bioinks, including tissue spheroids, tissue strands, cell pellets, decellularized matrix components, micro-carriers and cellladen hydrogels, the technology currently faces several limitations and challenges. These include impediments to organ fabrication, the limited resolution of printed features, the need for advanced bioprinting solutions to transition the technology bench to bedside, the necessity of new bioink development for rapid, safe and sustainable delivery of cells in a biomimetically organized microenvironment, and regulatory concerns to transform the technology into a product. This paper, presenting a first-time comprehensive review of EBB, discusses the current advancements in EBB technology and highlights future directions to transform the technology to generate viable end products for tissue engineering and regenerative medicine.

The purpose of the study was to determine the effects of static and dynamic stretching protocols within general and activity specific warm-ups. Nine male and ten female subjects were tested under four warm-up conditions including a 1) general aerobic warm-up with static stretching, 2) general aerobic warm-up with dynamic stretching, 3) general and specific warm-up with static stretching and 4) general and specific warm-up with dynamic stretching. Following all conditions, subjects were tested for movement time (kicking movement of leg over 0.5 m distance), countermovement jump height, sit and reach flexibility and 6 repetitions of 20 metre sprints. Results indicated that when a sport specific warm-up was included, there was an 0.94% improvement (p = 0.0013) in 20 meter sprint time with both the dynamic and static stretch groups. No such difference in sprint performance between dynamic and static stretch groups existed in the absence of the sport specific warm-up. The static stretch ...