Powered protrusion cutter

DOEpatents

Bzorgi, Fariborz M.

2010-03-09

An apparatus for clipping a protrusion of material is provided. The protrusion may, for example, be a bolt head, a nut, a rivet, a weld bead, or a temporary assembly alignment tab protruding from a substrate surface of assembled components. The apparatus typically includes a cleaver having a cleaving edge and a cutting blade having a cutting edge. Generally, a mounting structure configured to confine the cleaver and the cutting blade and permit a range of relative movement between the cleaving edge and the cutting edge is provided. Also typically included is a power device coupled to the cutting blade. The power device is configured to move the cutting edge toward the cleaving edge. In some embodiments the power device is activated by a momentary switch. A retraction device is also generally provided, where the retraction device is configured to move the cutting edge away from the cleaving edge.

Drilling of CFRP and GFRP composite laminates using one shot solid carbide step drill K44

NASA Astrophysics Data System (ADS)

Nagaraja, R.; Rangaswamy, T.

2018-04-01

Drilling is a very common machining operation to install fasteners for assembly of laminates Drilling of Carbon Fiber Reinforced Plastic (CFRP) and Glass Fiber Reinforced Plastic (GFRP) composite laminate materials are different from that of convention materials that causes excessive tool wear and edge delamination. This paper reports on the tool geometry, cutting speed and feed rate. In this work two composite materials CFRP-G926 and Glass-7781 composite materials of varying thickness are drilled to investigate the effect of feed rate, and cutting speed. The study mainly focused on drilling laminates specimen of varying thickness 9 mm, 9.6 mm and 12 mm by using a single shot solid carbide step drill K44. The drilling is performed from lower to higher feed rate and cutting speed to investigate the hole quality, bottom top edge delamination, fiber breakages and local cracks. The work performed shows that a proper combination of tool geometry, cutting speed and feed rate can help to reduce the occurrence of delamination.

CPU-GPU mixed implementation of virtual node method for real-time interactive cutting of deformable objects using OpenCL.

PubMed

Jia, Shiyu; Zhang, Weizhong; Yu, Xiaokang; Pan, Zhenkuan

2015-09-01

Surgical simulators need to simulate interactive cutting of deformable objects in real time. The goal of this work was to design an interactive cutting algorithm that eliminates traditional cutting state classification and can work simultaneously with real-time GPU-accelerated deformation without affecting its numerical stability. A modified virtual node method for cutting is proposed. Deformable object is modeled as a real tetrahedral mesh embedded in a virtual tetrahedral mesh, and the former is used for graphics rendering and collision, while the latter is used for deformation. Cutting algorithm first subdivides real tetrahedrons to eliminate all face and edge intersections, then splits faces, edges and vertices along cutting tool trajectory to form cut surfaces. Next virtual tetrahedrons containing more than one connected real tetrahedral fragments are duplicated, and connectivity between virtual tetrahedrons is updated. Finally, embedding relationship between real and virtual tetrahedral meshes is updated. Co-rotational linear finite element method is used for deformation. Cutting and collision are processed by CPU, while deformation is carried out by GPU using OpenCL. Efficiency of GPU-accelerated deformation algorithm was tested using block models with varying numbers of tetrahedrons. Effectiveness of our cutting algorithm under multiple cuts and self-intersecting cuts was tested using a block model and a cylinder model. Cutting of a more complex liver model was performed, and detailed performance characteristics of cutting, deformation and collision were measured and analyzed. Our cutting algorithm can produce continuous cut surfaces when traditional minimal element creation algorithm fails. Our GPU-accelerated deformation algorithm remains stable with constant time step under multiple arbitrary cuts and works on both NVIDIA and AMD GPUs. GPU-CPU speed ratio can be as high as 10 for models with 80,000 tetrahedrons. Forty to sixty percent real-time performance and 100-200 Hz simulation rate are achieved for the liver model with 3,101 tetrahedrons. Major bottlenecks for simulation efficiency are cutting, collision processing and CPU-GPU data transfer. Future work needs to improve on these areas.

Edge-Dependent Electronic and Magnetic Characteristics of Freestanding β 12-Borophene Nanoribbons

NASA Astrophysics Data System (ADS)

Izadi Vishkayi, Sahar; Bagheri Tagani, Meysam

2018-03-01

This work presents an investigation of nanoribbons cut from β 12-borophene sheets by applying the density functional theory. In particular, the electronic and magnetic properties of borophene nanoribbons (BNR) are studied. It is found that all the ribbons considered in this work behave as metals, which is in good agreement with the recent experimental results. β 12-BNR has significant diversity due to the existence of five boron atoms in a unit cell of the sheet. The magnetic properties of the ribbons are strongly dependent on the cutting direction and edge profile. It is interesting that a ribbon with a specific width can behave as a normal or a ferromagnetic metal with magnetization at just one edge or two edges. Spin anisotropy is observed in some ribbons, and the magnetic moment is not found to be the same in both edges in an antiferromagnetic configuration. This effect stems from the edge asymmetry of the ribbons and results in the breaking of spin degeneracy in the band structure. Our findings show that β 12 BNRs are potential candidates for next-generation spintronic devices. [Figure not available: see fulltext.

Microcutting characteristics on the single crystal diamond tool with edge radius using molecular dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Jeong-Du; Moon, Chan-Hong

1995-12-31

Ultraprecision metal cutting (UPMC) technology which makes possible submicrometer form accuracy and manometer roughness is developed to reach the 1nm nominal (undeformed) thickness of cut. At this thickness level, a few of atom`s layers should be considered. In this paper using the Molecuar Dynamics simulation, the phenomena of microcutting with a subnanometer chip thickness, the cutting mechanism for tool edge configuration to consider the sharp edge and round edge tool, the cut material and cutting speed are evaluated. Cutting mechanism of subnanometer depth of cut is evaluated.

Force Modelling in Orthogonal Cutting Considering Flank Wear Effect

NASA Astrophysics Data System (ADS)

Rathod, Kanti Bhikhubhai; Lalwani, Devdas I.

2017-05-01

In the present work, an attempt has been made to provide a predictive cutting force model during orthogonal cutting by combining two different force models, that is, a force model for a perfectly sharp tool plus considering the effect of edge radius and a force model for a worn tool. The first force model is for a perfectly sharp tool that is based on Oxley's predictive machining theory for orthogonal cutting as the Oxley's model is for perfectly sharp tool, the effect of cutting edge radius (hone radius) is added and improve model is presented. The second force model is based on worn tool (flank wear) that was proposed by Waldorf. Further, the developed combined force model is also used to predict flank wear width using inverse approach. The performance of the developed combined total force model is compared with the previously published results for AISI 1045 and AISI 4142 materials and found reasonably good agreement.

Effects of Cutting Edge Microgeometry on Residual Stress in Orthogonal Cutting of Inconel 718 by FEM.

PubMed

Shen, Qi; Liu, Zhanqiang; Hua, Yang; Zhao, Jinfu; Lv, Woyun; Mohsan, Aziz Ul Hassan

2018-06-14

Service performance of components such as fatigue life are dramatically influenced by the machined surface and subsurface residual stresses. This paper aims at achieving a better understanding of the influence of cutting edge microgeometry on machined surface residual stresses during orthogonal dry cutting of Inconel 718. Numerical and experimental investigations have been conducted in this research. The cutting edge microgeometry factors of average cutting edge radius S¯, form-factor K , and chamfer were investigated. An increasing trend for the magnitudes of both tensile and compressive residual stresses was observed by using larger S¯ or introducing a chamfer on the cutting edges. The ploughing depth has been predicted based on the stagnation zone. The increase of ploughing depth means that more material was ironed on the workpiece subsurface, which resulted in an increase in the compressive residual stress. The thermal loads were leading factors that affected the surface tensile residual stress. For the unsymmetrical honed cutting edge with K = 2, the friction between tool and workpiece and tensile residual stress tended to be high, while for the unsymmetrical honed cutting edge with K = 0.5, the high ploughing depth led to a higher compressive residual stress. This paper provides guidance for regulating machine-induced residual stress by edge preparation.

Distribution of contact loads over the flank-land of the cutter with a rounded cutting edge

NASA Astrophysics Data System (ADS)

Kozlov, V.; Gerasimov, A.; Kim, A.

2016-04-01

In this paper, contact conditions between a tool and a workpiece material for wear-simulating turning by a cutter with a sharp-cornered edge and with a rounded cutting edge are analysed. The results of the experimental study of specific contact load distribution over the artificial flank wear-land of the cutter in free orthogonal turning of the disk from titanium alloy (Ti6Al2Mo2Cr), ductile (63Cu) and brittle (57Cu1Al3Mn) brasses are described. Investigations were carried out by the method of ‘split cutter’ and by the method of the artificial flank-land of variable width. The experiments with a variable feed rate and a cutting speed show that in titanium alloy machining with a sharp-cornered cutting edge the highest normal contact load (σh max = 3400…2200 MPa) is observed immediately at the cutting edge, and the curve has a horizontal region with the length of 0.2… 0.6 mm. At a distance from the cutting edge, the value of specific normal contact load is dramatically reduced to 1100…500 MPa. The character of normal contact load for a rounded cutting edge is different -it is uniform, and its value is approximately 2 times smaller compared to machining with a sharp-cornered cutting edge. In author’s opinion it is connected with generation of a seizure zone in a chip formation region and explains the capacity of highly worn-out cutting tools for titanium alloys machining. The paper analyses the distribution of tangential contact loads over the flank land, which pattern differs considerably for machining with a sharp-cornered edge and with a rounded cutting edge. Abbreviation and symbols: m/s - meter per second (cutting speed v); mm/r - millimeter per revolution (feed rate f); MPa - mega Pascal (specific contact load as a stress σ or τ) hf - the width of the flank wear land (chamfer) of the cutting tool, flank wear land can be natural or artificial like the one in this paper [mm]; xh - distance from the cutting edge on the surface of the flank-land [mm]; σh - normal specific contact load on the flank land [MPa]; τh - tangential (shear) specific contact load on the flank land [MPa]; HSS - high speed steel (material of cutting tool); Py - radial component of cutting force [N]; Py r - radial component of cutting force on the rake face [N]; Pz - tangential component of cutting force [N]; γ - rake angle of the cutting tool [°] α - clearance angle of the sharp cutting tool [°] αh - clearance angle of the flank wear land [°] ρ - rounding off radius of the cutting edge [mm]; b - width of the machined disk [mm].

An ultra-precision tool nanoindentation instrument for replication of single point diamond tool cutting edges

NASA Astrophysics Data System (ADS)

Cai, Yindi; Chen, Yuan-Liu; Xu, Malu; Shimizu, Yuki; Ito, So; Matsukuma, Hiraku; Gao, Wei

2018-05-01

Precision replication of the diamond tool cutting edge is required for non-destructive tool metrology. This paper presents an ultra-precision tool nanoindentation instrument designed and constructed for replication of the cutting edge of a single point diamond tool onto a selected soft metal workpiece by precisely indenting the tool cutting edge into the workpiece surface. The instrument has the ability to control the indentation depth with a nanometric resolution, enabling the replication of tool cutting edges with high precision. The motion of the diamond tool along the indentation direction is controlled by the piezoelectric actuator of a fast tool servo (FTS). An integrated capacitive sensor of the FTS is employed to detect the displacement of the diamond tool. The soft metal workpiece is attached to an aluminum cantilever whose deflection is monitored by another capacitive sensor, referred to as an outside capacitive sensor. The indentation force and depth can be accurately evaluated from the diamond tool displacement, the cantilever deflection and the cantilever spring constant. Experiments were carried out by replicating the cutting edge of a single point diamond tool with a nose radius of 2.0 mm on a copper workpiece surface. The profile of the replicated tool cutting edge was measured using an atomic force microscope (AFM). The effectiveness of the instrument in precision replication of diamond tool cutting edges is well-verified by the experimental results.

CUTTING AND WEDGING JACKET REMOVER

DOEpatents

Freedman, M.; Raynor, S.

1959-04-01

A tool is presented for stripping cladded jackets from fissionable fuel elements. The tool is a tube which fits closely around the jacket and which has two cutting edges at opposite sides of one end. These cutting edges are adjusted to penetrate only the jacket so that by moving the edges downward the jacket is cut into two pieces.

WWBT? What Would Ben Think about Killer Apps, Cutting Edges, and Tipping Points in the History of Weather and Climate?

NASA Astrophysics Data System (ADS)

Fleming, J. R.

2006-12-01

This paper examines the history of weather and climate since 1706 along three intertwined analytical axes: technology (killer apps), science (cutting edges), and social issues (tipping points). For example, Franklin's best-known killer app, the lightning rod, gains added significance when seen in light of his cutting edge contributions to the science of electricity, his lifelong promotion of useful knowledge, and the societal tipping point his work triggered in our relationship to the sky. Subsequently, other major tipping points and conceptual shifts followed the introduction of telegraphy, radio, television, digital computers, and rocketry into meteorology. Following an analysis of the career and contributions of Benjamin Franklin (1706-1790), the paper examines later historical moments and watersheds, not merely in retrospect, but from the perspective of leading participants at the time. It focuses on technologies of significant promise, especially those involving electro- magnetism, up to and including the dawn of the twenty-first century, and asks playfully, "What would Ben think?"

Cutting tool form compensation system and method

DOEpatents

Barkman, W.E.; Babelay, E.F. Jr.; Klages, E.J.

1993-10-19

A compensation system for a computer-controlled machining apparatus having a controller and including a cutting tool and a workpiece holder which are movable relative to one another along a preprogrammed path during a machining operation utilizes a camera and a vision computer for gathering information at a preselected stage of a machining operation relating to the actual shape and size of the cutting edge of the cutting tool and for altering the preprogrammed path in accordance with detected variations between the actual size and shape of the cutting edge and an assumed size and shape of the cutting edge. The camera obtains an image of the cutting tool against a background so that the cutting tool and background possess contrasting light intensities, and the vision computer utilizes the contrasting light intensities of the image to locate points therein which correspond to points along the actual cutting edge. Following a series of computations involving the determining of a tool center from the points identified along the tool edge, the results of the computations are fed to the controller where the preprogrammed path is altered as aforedescribed. 9 figures.

Cutting tool form compensaton system and method

DOEpatents

Barkman, William E.; Babelay, Jr., Edwin F.; Klages, Edward J.

1993-01-01

A compensation system for a computer-controlled machining apparatus having a controller and including a cutting tool and a workpiece holder which are movable relative to one another along a preprogrammed path during a machining operation utilizes a camera and a vision computer for gathering information at a preselected stage of a machining operation relating to the actual shape and size of the cutting edge of the cutting tool and for altering the preprogrammed path in accordance with detected variations between the actual size and shape of the cutting edge and an assumed size and shape of the cutting edge. The camera obtains an image of the cutting tool against a background so that the cutting tool and background possess contrasting light intensities, and the vision computer utilizes the contrasting light intensities of the image to locate points therein which correspond to points along the actual cutting edge. Following a series of computations involving the determining of a tool center from the points identified along the tool edge, the results of the computations are fed to the controller where the preprogrammed path is altered as aforedescribed.

Cutting roller

DOE Office of Scientific and Technical Information (OSTI.GOV)

Best, G.; Weikert, N.B.

1984-05-29

A cutting roller for a mining machine, having a substantially conical closure member arranged to face the workings and a tubular body member which has a larger diameter at the end nearer the face working face than at the discharge end. The tubular member carries at least one cutting blade, and the closure member mounts at least one cutting blade; each blade is provided at its edge region with a plurality of bit holders for the attachment of cutter bits. The outer surface of the body member merges into the substantially conical closure member in a smooth, even curve, somore » that the outside diameter of the body member in the region of the working face is substantially greater than the diameter in the region of the discharge end of the cutting roller. The roller is provided with liquid distribution channels on each cutting blade, which channels are connected to a single liquid distribution ring channel in the region of the substantially conical closure member.« less

Investigation of the Effect of Tool Edge Geometry upon Cutting Variables, Tool Wear and Burr Formation Using Finite Element Simulation — A Progress Report

NASA Astrophysics Data System (ADS)

Sartkulvanich, Partchapol; Al-Zkeri, Ibrahim; Yen, Yung-Chang; Altan, Taylan

2004-06-01

This paper summarizes some of the progress made on FEM simulations of metal cutting processes conducted at the Engineering Research Center (ERC/NSM). Presented research focuses on the performance of various cutting edge geometries (hone and chamfer edges) for different tool materials and specifically on: 1) the effect of round and chamfer edge geometries on the cutting variables in machining carbon steels and 2) the effect of the edge hone size upon the flank wear and burr formation behavior in face milling of A356-T6 aluminum alloy. In the second task, an innovative design of edge preparation with varying hone size around the tool nose is also explored using FEM. In order to model three-dimensional conventional turning and face milling with two-dimensional orthogonal cutting simulations, 2D simulation cross-sections consisting of the cutting speed direction and chip flow direction are selected at different locations along the tool nose radius. Then the geometries of the hone and chamfer edges and their associated tool angles as well as uncut chip thickness are determined on these planes and employed in cutting simulations. The chip flow direction on the tool rake face are obtained by examining the wear grooves on the experimental inserts or estimated by using Oxley's approximation theory of oblique cutting. Simulation results are compared with the available experimental results (e.g. cutting forces) both qualitatively and quantitatively.

Influence of the cutting edge angle of a titanium instrument on chip formation in the machining of trabecular and cortical bone.

PubMed

von See, Constantin; Stoetzer, Marcus; Ruecker, Martin; Wagner, Max; Schumann, Paul; Gellrich, Nils-Claudius

2014-01-01

The placement of self-tapping implants is associated with microfractures and the formation of bone chips along the cutting flutes. This study was conducted to investigate the effect of different cutting edge angles on chip formation during the machining of trabecular and cortical bone using instruments with a rough titanium surface. Mandibular cortical and trabecular bone specimens were obtained from freshly slaughtered domestic pigs. A predefined thrust force was applied to the specimens. Four specially designed cutting instruments that simulated dental implants and had a rough titanium surface were allowed to complete one full revolution at cutting edge angles of 55, 65, 75, and 85 degrees, respectively. Torque and thrust were measured during the cutting process. Bone chips were measured and weighed under a microscope. Different cutting edge angles did not lead to significant differences in torque. The lowest torque values were measured when the cutting edges were positioned at 65 degrees in trabecular bone and at 85 degrees in cortical bone. Bone chips were significantly larger and heavier at angles of 55 and 65 degrees than at angles of 75 and 85 degrees in trabecular bone. Instruments with a rough titanium surface show considerable angle-dependent differences in chip formation. In addition to bone density, the angle of the cutting edges should be taken into consideration during the placement of dental implants. Good results were obtained when the cutting edges were positioned at an angle of 65 degrees. This angle can have positive effects on osseointegration.

Development of a 2-stage shear-cutting-process to reduce cut-edge-sensitivity of steels

NASA Astrophysics Data System (ADS)

Gläsner, T.; Sunderkötter, C.; Hoffmann, H.; Volk, W.; Golle, R.

2017-09-01

The edge cracking sensitivity of AHSS and UHSS is a challenging factor in the cold forming process. Expanding cut holes during flanging operations is rather common in automotive components. During these flanging operations the pierced hole is stretched so that its diameter is increased. These flanging operations stretch material that has already been subjected to large amounts of plastic deformation, therefore forming problems may occur. An innovative cutting process decreases micro cracks in the cutting surface and facilitates the subsequent cold forming process. That cutting process consists of two stages, which produces close dimensional tolerance and smooth edges. As a result the hole expanding ratio was increased by nearly 100 % when using thick high strength steels for suspension components. The paper describes the mechanisms of the trimming process at the cut edge, and the positive effect of the 2-stage shear-cutting process on the hole extension capability of multiphase steels.

Gender and Choice in Education and Occupation.

ERIC Educational Resources Information Center

Radford, John, Ed.

Nine chapters present cutting-edge research on "brainsex" and its effects on personality, education, and choice. It targets concepts such as job attributes, work flexibility, long-term life planning, home-work conflict, prestige versus occupational interest, and intrinsic motivational mechanisms to explain the relative failure of…

Iron aluminide knife and method thereof

DOEpatents

Sikka, Vinod K.

1997-01-01

Fabricating an article of manufacture having a Fe.sub.3 Al-based alloy cutting edge. The fabrication comprises the steps of casting an Fe.sub.3 Al-based alloy, extruding into rectangular cross section, rolling into a sheet at 800.degree. C. for a period of time followed by rolling at 650.degree. C., cutting the rolled sheet into an article having an edge, and grinding the edge of the article to form a cutting edge.

Characterization of Flame Cut Heavy Steel: Modeling of Temperature History and Residual Stress Formation

NASA Astrophysics Data System (ADS)

Jokiaho, T.; Laitinen, A.; Santa-aho, S.; Isakov, M.; Peura, P.; Saarinen, T.; Lehtovaara, A.; Vippola, M.

2017-12-01

Heavy steel plates are used in demanding applications that require both high strength and hardness. An important step in the production of such components is cutting the plates with a cost-effective thermal cutting method such as flame cutting. Flame cutting is performed with a controlled flame and oxygen jet, which burns the steel and forms a cutting edge. However, the thermal cutting of heavy steel plates causes several problems. A heat-affected zone (HAZ) is generated at the cut edge due to the steep temperature gradient. Consequently, volume changes, hardness variations, and microstructural changes occur in the HAZ. In addition, residual stresses are formed at the cut edge during the process. In the worst case, unsuitable flame cutting practices generate cracks at the cut edge. The flame cutting of thick steel plate was modeled using the commercial finite element software ABAQUS. The results of modeling were verified by X-ray diffraction-based residual stress measurements and microstructural analysis. The model provides several outcomes, such as obtaining more information related to the formation of residual stresses and the temperature history during the flame cutting process. In addition, an extensive series of flame cut samples was designed with the assistance of the model.

Cutting Edge Technologies Presentation: An Overview of Developing Sensor Technology Directions and Possible Barriers to New Technology Implementation

NASA Technical Reports Server (NTRS)

Hunter, Gary W.

2007-01-01

The aerospace industry requires the development of a range of chemical sensor technologies for such applications as leak detection, emission monitoring, fuel leak detection, environmental monitoring, and fire detection. A range of chemical sensors are being developed based on micromachining and microfabrication technology to fabricate microsensors with minimal size, weight, and power consumption; and the use of nanomaterials and structures to develop sensors with improved stability combined with higher sensitivity, However, individual sensors are limited in the amount of information that they can provide in environments that contain multiple chemical species. Thus, sensor arrays are being developed to address detection needs in such multi-species environments. These technologies and technical approaches have direct relevance to breath monitoring for clinical applications. This presentation gives an overview of developing cutting-edge sensor technology and possible barriers to new technology implementation. This includes lessons learned from previous microsensor development, recent work in development of a breath monitoring system, and future directions in the implementation of cutting edge sensor technology.

Laser cutting of Kevlar laminates and thermal stress formed at cutting sections

NASA Astrophysics Data System (ADS)

Yilbas, B. S.; Akhtar, S. S.

2012-02-01

Laser cutting of Kevlar laminates is carried out and thermal stress field developed in the cutting region is predicted using the finite element code. Temperature predictions are validated through the thermocouple data. The morphological changes in the cutting section are examined by incorporating optical and scanning electron microscopes. It is found that temperature predictions agree well with the thermocouple data. High values of von Mises stress are observed at the cutting edges and at the mid-thickness of the Kevlar laminate due to thermal compression formed in this region. The laser cut edges are free from whiskers; however, striation formation and some small sideways burning is observed at the kerf edges.

Cutting-Edge: Integrating Students with Intellectual and Developmental Disabilities into a 4-Year Liberal Arts College

ERIC Educational Resources Information Center

Hafner, Dedra; Moffatt, Courtney; Kisa, Nutullah

2011-01-01

Cutting-Edge provides inclusion in college for students with intellectual disabilities (SWID). Cutting-Edge students attended college by taking undergraduate courses, resided in student housing, and engaged in student-life events as well as pursued community service, internships and employment. Undergraduate students were the best means to teach…

Finite Element Simulations of Micro Turning of Ti-6Al-4V using PCD and Coated Carbide tools

NASA Astrophysics Data System (ADS)

Jagadesh, Thangavel; Samuel, G. L.

2017-02-01

The demand for manufacturing axi-symmetric Ti-6Al-4V implants is increasing in biomedical applications and it involves micro turning process. To understand the micro turning process, in this work, a 3D finite element model has been developed for predicting the tool chip interface temperature, cutting, thrust and axial forces. Strain gradient effect has been included in the Johnson-Cook material model to represent the flow stress of the work material. To verify the simulation results, experiments have been conducted at four different feed rates and at three different cutting speeds. Since titanium alloy has low Young's modulus, spring back effect is predominant for higher edge radius coated carbide tool which leads to the increase in the forces. Whereas, polycrystalline diamond (PCD) tool has smaller edge radius that leads to lesser forces and decrease in tool chip interface temperature due to high thermal conductivity. Tool chip interface temperature increases by increasing the cutting speed, however the increase is less for PCD tool as compared to the coated carbide tool. When uncut chip thickness decreases, there is an increase in specific cutting energy due to material strengthening effects. Surface roughness is higher for coated carbide tool due to ploughing effect when compared with PCD tool. The average prediction error of finite element model for cutting and thrust forces are 11.45 and 14.87 % respectively.

Numerical approach in defining milling force taking into account curved cutting-edge of applied mills

NASA Astrophysics Data System (ADS)

Bondarenko, I. R.

2018-03-01

The paper tackles the task of applying the numerical approach to determine the cutting forces of carbon steel machining with curved cutting edge mill. To solve the abovementioned task the curved surface of the cutting edge was subject to step approximation, and the chips section was split into discrete elements. As a result, the cutting force was defined as the sum of elementary forces observed during the cut of every element. Comparison and analysis of calculations with regard to the proposed method and the method with Kienzle dependence showed its sufficient accuracy, which makes it possible to apply the method in practice.

Iron aluminide knife and method thereof

DOEpatents

Sikka, V.K.

1997-08-05

Fabricating an article of manufacture having a Fe{sub 3}Al-based alloy cutting edge is discussed. The fabrication comprises the steps of casting an Fe{sub 3}Al-based alloy, extruding into rectangular cross section, rolling into a sheet at 800 C for a period of time followed by rolling at 650 C, cutting the rolled sheet into an article having an edge, and grinding the edge of the article to form a cutting edge. 1 fig.

CONASTA Brings Teachers a Kaleidoscope of Science

ERIC Educational Resources Information Center

Teaching Science, 2015

2015-01-01

From star systems to social systems, CONASTA 64 connects teachers to researchers and scientists working on the cutting edge of modern science. We asked two CONASTA 64 Keynote speakers, Steven Tingay and Ian Walker to share their passion for their work and their dedication for giving back to the science community.

High-Speed Edge Trimming of CFRP and Online Monitoring of Performance of Router Tools Using Acoustic Emission

PubMed Central

Prakash, Rangasamy; Krishnaraj, Vijayan; Zitoune, Redouane; Sheikh-Ahmad, Jamal

2016-01-01

Carbon fiber reinforced polymers (CFRPs) have found wide-ranging applications in numerous industrial fields such as aerospace, automotive, and shipping industries due to their excellent mechanical properties that lead to enhanced functional performance. In this paper, an experimental study on edge trimming of CFRP was done with various cutting conditions and different geometry of tools such as helical-, fluted-, and burr-type tools. The investigation involves the measurement of cutting forces for the different machining conditions and its effect on the surface quality of the trimmed edges. The modern cutting tools (router tools or burr tools) selected for machining CFRPs, have complex geometries in cutting edges and surfaces, and therefore a traditional method of direct tool wear evaluation is not applicable. An acoustic emission (AE) sensing was employed for on-line monitoring of the performance of router tools to determine the relationship between AE signal and length of machining for different kinds of geometry of tools. The investigation showed that the router tool with a flat cutting edge has better performance by generating lower cutting force and better surface finish with no delamination on trimmed edges. The mathematical modeling for the prediction of cutting forces was also done using Artificial Neural Network and Regression Analysis. PMID:28773919

Determination of functions of controlling drives of main executive mechanisms of mining excavators

NASA Astrophysics Data System (ADS)

Lagunova, Yu A.; Komissarov, A. P.; Lukashuk, O. A.

2018-03-01

It is shown that a special shovel is a feature of the structure of the drives of the main mechanisms (mechanisms of lifting and pressure) of career excavators with working equipment, the presence in the transfer device of a two-crank-lever mechanism of working equipment that connects the main mechanisms with the working body (bucket). In this case, the transformation of the mechanical energy parameters of the motors into energy-force parameters realized at the cutting edge of the bucket (teeth) takes place depending on the type of the kinematic scheme of the two-link-lever mechanism. The concept of “control function” defining the relationship between the parameters characterizing the position of the bucket in the face (the coordinates of the tip of the cutting edge of the bucket, the digging speed) and the required control level are introduced. These are the values of the lifting and head speeds ensuring the bucket movement along a given trajectory.

Impact of high-pressure coolant supply on chip formation in milling

NASA Astrophysics Data System (ADS)

Klocke, F.; Döbbeler, B.; Lakner, T.

2017-10-01

Machining of titanium alloys is considered as difficult, because of their high temperature strength, low thermal conductivity and low E-modulus, which contributes to high mechanical loads and high temperatures in the contact zone between tool and workpiece. The generated heat in the cutting zone can be dissipated only in a low extent. When cutting steel materials, up to 75% of the process heat is transported away by the chips, contrary to only 25% when machining titanium alloys. As a result, the cutting tool heats up, which leads to high tool wear. Therefore, machining of titanium alloys is only possible with relatively low cutting speeds. This leads to low levels of productivity for milling processes with titanium alloys. One way to increase productivity is to use more cutting edges in tools with the same diameter. However, the limiting factor of adding more cutting edges to a milling tool is the minimum size of the chip spaces, which are sufficient for a stable chip evacuation. This paper presents experimental results on the chip formation and chip size influenced by high-pressure coolant supply, which can lead to smaller chips and to smaller sizes of the chip spaces, respectively. Both influences, the pressure of the supplied coolant and the volumetric flow rate were individually examined. Alpha-beta annealed titanium TiAl6V4 was examined in relation to the reference material quenched and tempered steel 42CrMo4+QT (AISI 4140+QT). The work shows that with proper chip control due to high-pressure coolant supply in milling, the number of cutting edges on the same diameter tool can be increased, which leads to improved productivity.

Double diameter boring tool

DOEpatents

Ashbaugh, Fred N.; Murry, Kenneth R.

1988-12-27

A boring tool and a method of operation are provided for boring two concentric holes of precision diameters and depths in a single operation. The boring tool includes an elongated tool body, a shank for attachment to a standard adjustable boring head which is used on a manual or numerical control milling machine and first and second diametrically opposed cutting edges formed for cutting in opposite directions. The diameter of the elongated tool body is substantially equal to the distance from the first cutting edge tip to the axis of rotation plus the distance from the second cutting edge tip to the axis of rotation. The axis of rotation of the tool is spaced from the tool centerline a distance substantially equal to one-half the distance from the second cutting edge tip to the axis of rotation minus one-half the distance from the first cutting edge tip to the axis of rotation. The method includes the step of inserting the boring tool into the boring head, adjusting the distance between the tool centerline and the tool axis of rotation as described above and boring the two concentric holes.

Real Science, Real Classrooms

ERIC Educational Resources Information Center

Parker, Becky

2017-01-01

The Institute for Research in Schools (IRIS) was set up to give science students the opportunity to work on cutting-edge research projects. Teachers and students can access data and equipment that enable them to tackle real-life issues. As a result, not only do students gain in confidence and experience in their scientific work, they are also able…

Double diameter boring tool

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ashbaugh, F.N.; Murry, K.R.

A method of boring two concentric holes of different depths is described utilizing an elongated boring tool having a tool axis of rotation, a longitudinally disposed tool centerline axis, and first and second transverse cutting edges at one end thereof extending across the boring tool, the second cutting edge being longitudinally rearwardly recessed with respect to the first cutting edge. The method consists of inserting the boring tool into an adjustable boring head, adjusting a distance B between the tool centerline axis and the tool axis of rotation such that the tool axis of rotation intersects a first boring areamore » of the first cutting edge; and boring the concentric holes having respectively larger and smaller diameters.« less

An Introduction to the Work (and Play) of Writing Studies Research Methods through Micro Study

ERIC Educational Resources Information Center

Aiken, Suzan; Beard, Emily J.; McClure, David R. E.; Nickoson, Lee

2013-01-01

This article addresses the benefits and challenges involved with assigning small-scale research projects in one research methods class as means of introducing new(er) researchers to the work and rewards of empirical writing research. The following discussion does not claim to offer examples of cutting-edge methodological work. That is not our goal…

Shaping of Rack Cutter Original Profile for Fine-module Ratchet Teeth Cutting

NASA Astrophysics Data System (ADS)

Sharkov, O. V.; Koryagin, S. I.; Velikanov, N. L.

2018-05-01

The design models and the process of shaping the cutting edges of the rack cutter for cutting fine-module ratchet teeth are considered in the article. The use of fine-module ratchet teeth can reduce the noise and impact loads during operation of the freewheel mechanisms. Mathematical dependencies for calculating the coordinates determining the geometric position of the points of the front and back edges of the cutting profile of the rack cutter, the workpiece angle of rotation during cutting the ratchet teeth were obtained. When applying the developed method, the initial data are: the radii of the workpiece circumferences passing through the dedendum of the external and internal cut teeth; gradient angles of the front and back edges of the rail.

Grading technologies for the manufacture of innovative cutting blades

NASA Astrophysics Data System (ADS)

Rostek, Tim; Homberg, Werner

2018-05-01

Cutting blades for harvesting applications are used in a variety of agricultural machines. These parts are in contact with highly abrasive lawn clippings and often wear out within hours which results in high expensive re-sharpening maintenance. This paper relates to manufacturing techniques enhancing the durability of cutting blades based on a structural analysis of the prevailing wear mechanisms containing chipping and abrasive wear. Each mechanism results in specific demands on the cutting edge's mechanical characteristics. The design of evaluation methods respectively is one issue of the paper. This is basis for approaches to improve the cutting edge performance on purpose. On option to improve abrasive wear resistance and, thus, service life is the application of locally graded steel materials as semi-finished products for self-sharpening cutting blades. These materials comprise a layered structure consisting of a hard, wear resistant layer and a relatively softer layer which is lesser wear resistant. As the cutting blade is subjected to wear conditions, the less wear resistant layer wears faster than the relatively more wear resistant harder layer revealing a durable cross section of the cutting edge and, thus, cutting performance. Anyways, chipping is another key issue on the cutting edge's lifetime. Here, the cutting edges cross section by means of geometry and grind respectively as well as its mechanical properties matter. FEM analysis reveal innovative options to optimize the cross section of the blade as well as thermomechanical strengthening add further strength to reduce chipping. This paper contains a comprehensive strategy to improve cutting blades with use of innovative manufacturing technologies which apply application-specific graded mechanical characteristics and, thus, significantly improved performance characteristics.

Reducing contact resistance in graphene devices through contact area patterning.

PubMed

Smith, Joshua T; Franklin, Aaron D; Farmer, Damon B; Dimitrakopoulos, Christos D

2013-04-23

Performance of graphene electronics is limited by contact resistance associated with the metal-graphene (M-G) interface, where unique transport challenges arise as carriers are injected from a 3D metal into a 2D-graphene sheet. In this work, enhanced carrier injection is experimentally achieved in graphene devices by forming cuts in the graphene within the contact regions. These cuts are oriented normal to the channel and facilitate bonding between the contact metal and carbon atoms at the graphene cut edges, reproducibly maximizing "edge-contacted" injection. Despite the reduction in M-G contact area caused by these cuts, we find that a 32% reduction in contact resistance results in Cu-contacted, two-terminal devices, while a 22% reduction is achieved for top-gated graphene transistors with Pd contacts as compared to conventionally fabricated devices. The crucial role of contact annealing to facilitate this improvement is also elucidated. This simple approach provides a reliable and reproducible means of lowering contact resistance in graphene devices to bolster performance. Importantly, this enhancement requires no additional processing steps.

Global Oncology; Harvard Global Health Catalyst summit lecture notes

NASA Astrophysics Data System (ADS)

Ngwa, Wilfred; Nguyen, Paul

2017-08-01

The material presented in this book is at the cutting-edge of global oncology and provides highly illuminating examples, addresses frequently asked questions, and provides information and a reference for future work in global oncology care, research, education, and outreach.

Some aspects of precise laser machining - Part 2: Experimental

NASA Astrophysics Data System (ADS)

Grabowski, Marcin; Wyszynski, Dominik; Ostrowski, Robert

2018-05-01

The paper describes the role of laser beam polarization on quality of laser beam machined cutting tool edge. In micromachining the preparation of the cutting tools in play a key role on dimensional accuracy, sharpness and the quality of the cutting edges. In order to assure quality and dimensional accuracy of the cutting tool edge it is necessary to apply laser polarization control. In the research diode pumped Nd:YAG 532nm pulse laser was applied. Laser beam polarization used in the research was linear (horizontal, vertical). The goal of the carried out research was to describe impact of laser beam polarization on efficiency of the cutting process and quality of machined parts (edge, surface) made of polycrystalline diamond (PCD) and cubic boron nitride (cBN). Application of precise cutting tool in micromachining has significant impact on the minimum uncut chip thickness and quality of the parts. The research was carried within the INNOLOT program funded by the National Centre for Research and Development.

Field testing of alternative carbide edge snow plow blades : [technical memorandum].

DOT National Transportation Integrated Search

2004-03-01

The Maine Department of Transportation uses almost 2,500 carbide cutting edges on its fleet of highway snow plow trucks : each winter. This represents almost 9,000 linear ft. of cutting edges and an annual expenditure of roughly $150,000 each winter ...

Side Flow Effect on Surface Generation in Nano Cutting

NASA Astrophysics Data System (ADS)

Xu, Feifei; Fang, Fengzhou; Zhang, Xiaodong

2017-05-01

The side flow of material in nano cutting is one of the most important factors that deteriorate the machined surface quality. The effects of the crystallographic orientation, feed, and the cutting tool geometry, including tool edge radius, rake angle and inclination angle, on the side flow are investigated employing molecular dynamics simulation. The results show that the stagnation region is formed in front of tool edge and it is characterized by the stagnation radius R s and stagnation height h s . The side flow is formed because the material at or under the stagnation region is extruded by the tool edge to flow to the side of the tool edge. Higher stagnation height would increase the size of the side flow. The anisotropic nature of the material which partly determines the stagnation region also influences the side flow due to the different deformation mechanism under the action of the tool edge. At different cutting directions, the size of the side flow has a great difference which would finally affect the machined surface quality. The cutting directions of {100} < 011>, {110} < 001>, and {110} < 1-10 > are beneficial to obtain a better surface quality with small side flow. Besides that, the side flow could be suppressed by reducing the feed and optimizing the cutting tool geometry. Cutting tool with small edge radius, large positive rake angle, and inclination angle would decrease the side flow and consequently improve the machined surface quality.

Side Flow Effect on Surface Generation in Nano Cutting.

PubMed

Xu, Feifei; Fang, Fengzhou; Zhang, Xiaodong

2017-12-01

The side flow of material in nano cutting is one of the most important factors that deteriorate the machined surface quality. The effects of the crystallographic orientation, feed, and the cutting tool geometry, including tool edge radius, rake angle and inclination angle, on the side flow are investigated employing molecular dynamics simulation. The results show that the stagnation region is formed in front of tool edge and it is characterized by the stagnation radius R s and stagnation height h s . The side flow is formed because the material at or under the stagnation region is extruded by the tool edge to flow to the side of the tool edge. Higher stagnation height would increase the size of the side flow. The anisotropic nature of the material which partly determines the stagnation region also influences the side flow due to the different deformation mechanism under the action of the tool edge. At different cutting directions, the size of the side flow has a great difference which would finally affect the machined surface quality. The cutting directions of {100} < 011>, {110} < 001>, and {110} < 1-10 > are beneficial to obtain a better surface quality with small side flow. Besides that, the side flow could be suppressed by reducing the feed and optimizing the cutting tool geometry. Cutting tool with small edge radius, large positive rake angle, and inclination angle would decrease the side flow and consequently improve the machined surface quality.

Shaping Cutter Original Profile for Fine-module Ratchet Teeth Cutting

NASA Astrophysics Data System (ADS)

Sharkov, O. V.; Koryagin, S. I.; Velikanov, N. L.

2018-03-01

The methods for determining geometric characteristics of a theoretical original profile of the cutter for cutting ratchet teeth with a module of 0.3–1.0 mm are considered in the article. Design models describing the shaping process of cutting edges of cutter teeth are developed. Systems of expressions for determining coordinates of the points of front and back edges of cutter teeth; the workpiece angles of rotation during the cutting process; the minimum cutter radius are received. The basic data when using the proposed technique are: radii of circumferences passing through cavities of cutter teeth and external cut teeth; the gradient angle and length of straight section of the front edge of a cut tooth; angles of rotation of the cutter and the workpiece at the moment of shaping.

Preliminary results from field testing of alternative carbide edge snow plow blades.

DOT National Transportation Integrated Search

2003-04-01

The Maine Department of Transportation uses almost 2,500 carbide cutting edges on its fleet of highway snow plow trucks : each winter. This represents almost 9,000 linear ft. of cutting edges and an annual expenditure of roughly $150,000 each winter ...

Impact of the On the Cutting Edge Professional Development Program on U.S. Geoscience Faculty

NASA Astrophysics Data System (ADS)

Manduca, C. A.; Iverson, E. A.; Czujko, R.; Macdonald, H.; Mogk, D. W.; Tewksbury, B. J.; McLaughlin, J.; Sanford, C.; Greenseid, L.; Luxenberg, M.

2011-12-01

Transforming STEM education from a dominantly lecture-based format focused on facts to classrooms where students engage with the process of understanding the world through science is a primary goal of faculty development. On the Cutting Edge seeks to support this transformation by using workshops and a website to build a community of geoscience faculty who learn from one another. In order to assess the impact of the On the Cutting Edge program, we surveyed 5917 U.S. geoscience faculty in 2009 and received 2874 completed responses (49% response rate). We looked at the differences in responses between workshop participants who also use the website, website users who have not attended a Cutting Edge workshop, and survey respondents who had neither attended a Cutting Edge workshop nor used the Cutting Edge website. The number of respondents who had attended a Cutting Edge workshop and had not used the website was too small to analyze. Courses described by Cutting Edge workshop participants make significantly less use of lecture and more use of small group discussion and in-class activities. While all faculty respondents routinely update their courses, workshop participants are more likely to have changed their teaching methods in the two years leading up to the survey. When making changes to their teaching methods, workshop participants are more likely than other populations to seek information about teaching on the web, consult journal articles about teaching, and seek advice from colleagues outside their department and from nationally known leaders in geoscience education. Workshop participants are also more likely to tell a colleague when they do something that is particularly successful in class. End-of-workshop survey and follow-up interview data indicate that participants leave workshops reinvigorated, with a new or renewed commitment to student-centered teaching, and that they make use of the website as they implement ideas for changing their teaching following the workshop. Participants can identify specific ideas, techniques, and materials from workshops and the website that they have used in their teaching, and they attribute substantial improvements in their teaching to the Cutting Edge professional development experience. While the differences in behavior reported in the survey results may in part reflect the choice to attend workshops by faculty inclined to improve their teaching, the combination of motivation, attitude, and information developed through the workshop experience is amplifying this effect.

Cutting edge technology to enhance nursing classroom instruction at Coppin State University.

PubMed

Black, Crystal Day; Watties-Daniels, A Denyce

2006-01-01

Educational technologies have changed the paradigm of the teacher-student relationship in nursing education. Nursing students expect to use and to learn from cutting edge technology during their academic careers. Varied technology, from specified software programs (Tegrity and Blackboard) to the use of the Internet as a research medium, can enhance student learning. The authors provide an overview of current cutting edge technologies in nursing classroom instruction and its impact on future nursing practice.

CIDR

Science.gov Websites

quality, cutting-edge genomic services and technologies in order to expand our understanding of disease high quality next generation sequencing and genotyping services to investigators working to discover issues as they relate to study design, data production and quality control. Completed studies encompass

Multi-scale analytical investigation of fly ash in concrete

NASA Astrophysics Data System (ADS)

Aboustait, Mohammed B.

Much research has been conducted to find an acceptable concrete ingredient that would act as cement replacement. One promising material is fly ash. Fly ash is a by-product from coal-fired power plants. Throughout this document work on the characterization of fly ash structure and composition will be explored. This effort was conducted through a mixture of cutting edge multi-scale analytical X-ray based techniques that use both bulk experimentation and nano/micro analytical techniques. Furtherly, this examination was coupled by performing Physical/Mechanical ASTM based testing on fly ash-enrolled-concrete to examine the effects of fly ash introduction. The most exotic of the cutting edge characterization techniques endorsed in this work uses the Nano-Computed Tomography and the Nano X-ray Fluorescence at Argonne National Laboratory to investigate single fly ash particles. Additional Work on individual fly ash particles was completed by laboratory-based Micro-Computed Tomography and Scanning Electron Microscopy. By combining the results of individual particles and bulk property tests, a compiled perspective is introduced, and accessed to try and make new insights into the reactivity of fly ash within concrete.

Computation of two-dimensional flows past ram-air parachutes

NASA Astrophysics Data System (ADS)

Mittal, S.; Saxena, P.; Singh, A.

2001-03-01

Computational results for flow past a two-dimensional model of a ram-air parachute with leading edge cut are presented. Both laminar (Re=104) and turbulent (Re=106) flows are computed. A well-proven stabilized finite element method (FEM), which has been applied to various flow problems earlier, is utilized to solve the incompressible Navier-Stokes equations in the primitive variables formulation. The Baldwin-Lomax model is employed for turbulence closure. Turbulent flow computations past a Clarck-Y airfoil without a leading edge cut, for =7.5°, result in an attached flow. The leading edge cut causes the flow to become unsteady and leads to a significant loss in lift and an increase in drag. The flow inside the parafoil cell remains almost stagnant, resulting in a high value of pressure, which is responsible for giving the parafoil its shape. The value of the lift-to-drag ratio obtained with the present computations is in good agreement with those reported in the literature. The effect of the size and location of the leading edge cut is studied. It is found that the flow on the upper surface of the parafoil is fairly insensitive to the configuration of the cut. However, the flow quality on the lower surface improves as the leading edge cut becomes smaller. The lift-to-drag ratio for various configurations of the leading edge cut varies between 3.4 and 5.8. It is observed that even though the time histories of the aerodynamic coefficients from the laminar and turbulent flow computations are quite different, their time-averaged values are quite similar. Copyright

On the Cutting Edge: Workshops, Online Resources, and Community Development

NASA Astrophysics Data System (ADS)

Mogk, D. W.; Macdonald, H.; Manduca, C. A.; Tewksbury, B. J.; Fox, S.; Iverson, E. A. R.; Beane, R. J.; Mcconnell, D. A.; Wiese, K.; Wysession, M. E.

2014-12-01

On the Cutting Edge, funded by NSF since 2002, offers a comprehensive professional development program for geoscience faculty. The program includes an annual integrated in-person and virtual workshop series, has developed an extensive collection of peer-reviewed instructional activities and related online resources, and supports continuing community development through sponsorship of webinars, listservs, opportunities for community contributions, and dissemination of resources to keep faculty current in their science and pedagogic practices. On the Cutting Edge (CE) has offered more than 100 face-to-face and virtual workshops, webinars, journal clubs, and other events to more than 3000 participants. The award-winning website has more than 5000 pages including 47 modules on career management, pedagogy, and geoscience topics. It has more than 1800 instructional activities contributed by the community, the majority of which have been peer-reviewed. The website had more than one million visitors last year. We have worked to support a community in which faculty improve their teaching by designing courses using research-based methods to foster higher-order thinking, incorporate geoscience data, and address cognitive and affective aspects of learning as well as a community in which faculty are comfortable and successful in managing their careers. The program addresses the needs of faculty in all career stages at the full spectrum of institutions and covering the breadth of the geoscience curriculum. We select timely and compelling topics that attract different groups of participants. CE workshops are interactive, model best pedagogical practices, emphasize participant learning, provide opportunities for participants to share their knowledge and experience, provide high-quality resources, give participants time to reflect and to develop action plans, and help transform their ideas about teaching. On the Cutting Edge has had an impact on teaching based on data from national surveys, interview and classroom observation studies, and website usage. The Cutting Edge program is now part of the NAGT professional development program that includes face-to-face, traveling, and virtual workshops for faculty and geoscience programs of all types. http://serc.carleton.edu/NAGTWorkshops/index.html

Work with Us | Water Power | NREL

Science.gov Websites

the center's facilities and research and development capabilities. An aerial photo of buildings at the : Partner with us through technology partnership agreements. Participate in subcontracted water research through solicitations and requests for proposals. Use our cutting-edge research facilities to develop

Trendspotting 2011

ERIC Educational Resources Information Center

Thomas, Lisa Carlucci

2011-01-01

In this article, the author discusses Connecticut Library Consortium's (CLC) recently held fifth annual Trendspotting symposium, "E-books: Collections at the Crossroads." She was pleased to work with CLC to develop a cutting-edge program of dynamic, thought-provoking speakers and presentations, including an outstanding keynote by Eli Neiburger on…

Improving undergraduate STEM education: The efficacy of discipline-based professional development.

PubMed

Manduca, Cathryn A; Iverson, Ellen R; Luxenberg, Michael; Macdonald, R Heather; McConnell, David A; Mogk, David W; Tewksbury, Barbara J

2017-02-01

We sought to determine whether instructional practices used by undergraduate faculty in the geosciences have shifted from traditional teacher-centered lecture toward student-engaged teaching practices and to evaluate whether the national professional development program On the Cutting Edge (hereinafter Cutting Edge) has been a contributing factor in this change. We surveyed geoscience faculty across the United States in 2004, 2009, and 2012 and asked about teaching practices as well as levels of engagement in education research, scientific research, and professional development related to teaching. We tested these self-reported survey results with direct observations of teaching using the Reformed Teaching Observation Protocol, and we conducted interviews to understand what aspects of Cutting Edge have supported change. Survey data show that teaching strategies involving active learning have become more common, that these practices are concentrated in faculty who invest in learning about teaching, and that faculty investment in learning about teaching has increased. Regression analysis shows that, after controlling for other key influences, faculty who have participated in Cutting Edge programs and who regularly use resources on the Cutting Edge website are statistically more likely to use active learning teaching strategies. Cutting Edge participants also report that learning about teaching, the availability of teaching resources, and interactions with peers have supported changes in their teaching practice. Our data suggest that even one-time participation in a workshop with peers can lead to improved teaching by supporting a combination of affective and cognitive learning outcomes.

Improving undergraduate STEM education: The efficacy of discipline-based professional development

PubMed Central

Manduca, Cathryn A.; Iverson, Ellen R.; Luxenberg, Michael; Macdonald, R. Heather; McConnell, David A.; Mogk, David W.; Tewksbury, Barbara J.

2017-01-01

We sought to determine whether instructional practices used by undergraduate faculty in the geosciences have shifted from traditional teacher-centered lecture toward student-engaged teaching practices and to evaluate whether the national professional development program On the Cutting Edge (hereinafter Cutting Edge) has been a contributing factor in this change. We surveyed geoscience faculty across the United States in 2004, 2009, and 2012 and asked about teaching practices as well as levels of engagement in education research, scientific research, and professional development related to teaching. We tested these self-reported survey results with direct observations of teaching using the Reformed Teaching Observation Protocol, and we conducted interviews to understand what aspects of Cutting Edge have supported change. Survey data show that teaching strategies involving active learning have become more common, that these practices are concentrated in faculty who invest in learning about teaching, and that faculty investment in learning about teaching has increased. Regression analysis shows that, after controlling for other key influences, faculty who have participated in Cutting Edge programs and who regularly use resources on the Cutting Edge website are statistically more likely to use active learning teaching strategies. Cutting Edge participants also report that learning about teaching, the availability of teaching resources, and interactions with peers have supported changes in their teaching practice. Our data suggest that even one-time participation in a workshop with peers can lead to improved teaching by supporting a combination of affective and cognitive learning outcomes. PMID:28246629

Cutting thin glass by femtosecond laser ablation

NASA Astrophysics Data System (ADS)

Shin, Hyesung; Kim, Dongsik

2018-06-01

The femtosecond laser ablation process for cutting thin aluminoborosilicate glass sheets of thickness 100 μm was investigated with emphasis on effective cutting speed (Veff) and mechanical strength of diced samples. The process parameters including the laser fluence (F), overlap ratio (r) of the laser beam and polarization direction were varied at a fixed pulse repetition rate f = 1 kHz to find the optimal process condition that maximizes Veff and edge strength. A three-point bending test was performed to evaluate the front-side and back-side bending (edge) strength of the laser-cut samples. Veff was proportional to F unless r exceeded a critical value, at which excessive energy began to be delivered at the same spot. The front-side edge strength was bigger than the back-side strength because of the back-side damages such as chipping. Good edge strength, as high as ∼280 MPa (front-side) and ∼230 MPa (back-side), was obtained at F = 19 J/m2, r = 0.99, with laser polarization vertical to the cutting path.

Robot based deposition of WC-Co HVOF coatings on HSS cutting tools as a substitution for solid cemented carbide cutting tools

NASA Astrophysics Data System (ADS)

Tillmann, W.; Schaak, C.; Biermann, D.; Aßmuth, R.; Goeke, S.

2017-03-01

Cemented carbide (hard metal) cutting tools are the first choice to machine hard materials or to conduct high performance cutting processes. Main advantages of cemented carbide cutting tools are their high wear resistance (hardness) and good high temperature strength. In contrast, cemented carbide cutting tools are characterized by a low toughness and generate higher production costs, especially due to limited resources. Usually, cemented carbide cutting tools are produced by means of powder metallurgical processes. Compared to conventional manufacturing routes, these processes are more expensive and only a limited number of geometries can be realized. Furthermore, post-processing and preparing the cutting edges in order to achieve high performance tools is often required. In the present paper, an alternative method to substitute solid cemented carbide cutting tools is presented. Cutting tools made of conventional high speed steels (HSS) were coated with thick WC-Co (88/12) layers by means of thermal spraying (HVOF). The challenge is to obtain a dense, homogenous, and near-net-shape coating on the flanks and the cutting edge. For this purpose, different coating strategies were realized using an industrial robot. The coating properties were subsequently investigated. After this initial step, the surfaces of the cutting tools were ground and selected cutting edges were prepared by means of wet abrasive jet machining to achieve a smooth and round micro shape. Machining tests were conducted with these coated, ground and prepared cutting tools. The occurring wear phenomena were analyzed and compared to conventional HSS cutting tools. Overall, the results of the experiments proved that the coating withstands mechanical stresses during machining. In the conducted experiments, the coated cutting tools showed less wear than conventional HSS cutting tools. With respect to the initial wear resistance, additional benefits can be obtained by preparing the cutting edge by means of wet abrasive jet machining.

Machining of Silicon-Ribbon-Forming Dies

NASA Technical Reports Server (NTRS)

Menna, A. A.

1985-01-01

Carbon extension for dies used in forming silicon ribbon crystals machined precisely with help of special tool. Die extension has edges beveled toward narrow flats at top, with slot precisely oriented and centered between flats and bevels. Cutting tool assembled from standard angle cutter and circular saw or saws. Angle cutters cuts bevels while slot saw cuts slot between them. In alternative version, custom-ground edges or additional circular saws also cut flats simultaneously.

Work with Us | Wind | NREL

Science.gov Websites

our cutting-edge research facilities to develop, test, and evaluate wind technologies. License Our advantage of the center's facilities and research and development capabilities. An aerial photo of buildings wind-generated electricity. Companies partner with NREL when they have particular design challenges

Enhancing Teaching Excellence through a Scientist-Science Teacher Collaborative Process.

ERIC Educational Resources Information Center

Haakonsen, Harry; And Others

1993-01-01

The Institute for Science Instruction and Study (ISIS) at Southern Connecticut State University was established to place experienced science teachers in extended contact with a variety of research scientists working at the cutting edge of their fields. Reports program goals, format, requirements, and evaluation. (LZ)

Influence of edging practices on cutting yields of Alaska birch lumber

Treesearch

David L. Nicholls; J.W. Funck; C.C. Brunner; J.E. Reeb

2009-01-01

Birch lumber is often characterized by a high degree of knots, bark pockets, heartwood, and other features which force sawmill owners to decide whether to edge and trim boards to produce standard grade lumber vs. proprietary grade character-marked lumber. In addition, the edging strategies used with irregularly shaped flitches can greatly influence cut-stock recovery....

Characteristics and Machining Performance of TiN and TiAlN Coatings on a Milling Cutter

NASA Astrophysics Data System (ADS)

Sarwar, Mohammed; Haider, Julfikar

2011-01-01

Titanium Nitride (TiN) coating deposited by Physical Vapour Deposition (PVD) or Chemical Vapour Deposition (CVD) techniques on cutting tools (single point or multipoint) has contributed towards the improvement of tool life, productivity and product quality [1]. Addition of Al in TiN coating (e.g., TiAlN or AlTiN) has further improved the coating properties required for machining applications [2, 3]. This work presents a comparative investigation on TiN and TiAlN coatings deposited on to a Powder Metallurgy High Speed Steel (PM HSS) milling cutter used for machining bimetal (M42+D6A) steel strips. PVD (Arc evaporation) technique was used to deposit the coatings after carefully preparing the cutting edges of the milling cutter. Microstructure, chemical composition, hardness and adhesion of the coatings have been characterised using different techniques. The incorporation of Al into TiN coating results in an improvement in hardness, wear resistance and cutting performance. Examination of the worn flank in the coated cutting edges revealed that abrasive and adhesive wear are the predominant failure mechanisms. Tool designers, coating suppliers and manufacturing engineers could benefit from the information provided.

Commissioning a hobby cutting device for radiochromic film preparation.

PubMed

Zolfaghari, Somayeh; Francis, Kirby E; Kairn, Tanya; Crowe, Scott B

2017-06-01

In addition to a high spatial resolution and well characterised dose response, one of the major advantages of radiochromic film as a dosimeter is that sheets of film can be cut into pieces suitable for use as calibration films, and for in vivo and phantom measurements. The cutting of film is typically done using scissors or a guillotine, and this process can be time-consuming, limited in precision, requires extensive handling and does not allow holes to be cut from the film without cutting from an existing edge. This study investigated the use of a Brother ScanNCut hobby cutting system for EBT3 film preparation. The optimal operating parameters (blade size, pressure, speed) that resulted in precise cuts with minimal delamination at cut edges were identified using test cutting patterns. These parameters were then used to cut a large film insert for a stereotactic head phantom for comparison against an insert cut with scissors. While the hobby cutting system caused a wider region of delamination at the film edge (1.8 mm) compared to scissors (1 mm), the hobby cutting system was found to be able to produce reproducible cuts more efficiently and more accurately than scissors. The use of the hobby cutting system is recommended for complex phantom inserts (containing sharp corners or holes for alignment rods) or in situations where large numbers of film pieces need to be prepared.

Study on processing parameters of glass cutting by nanosecond 532 nm fiber laser

NASA Astrophysics Data System (ADS)

Wang, Jin; Gao, Fan; Xiong, Baoxing; Zhang, Xiang; Yuan, Xiao

2018-03-01

The processing parameters of soda-lime glass cutting with several nanosecond 532 nm pulsed fiber laser are studied in order to obtain sufficiently large ablation rate and better processing quality. The influences of laser processing parameters on effective cutting speed and cutting quality of 1 2 mm thick soda-lime glass are studied. The experimental results show that larger laser pulse energy will lead to higher effective cutting speed and larger maximum edge collapse of the front side of the glass samples. Compared with that of 1.1 mm thick glass samples, the 2.0 mm thick glass samples is more difficult to cut. With the pulse energy of 51.2 μJ, the maximum edge collapse is more than 200 μm for the 2.0 mm thick glass samples. In order to achieve the high effective cutting speed and good cutting quality at the same time, the dual energy overlapping method is used to obtain the better cutting performance for the 2.0 mm thick glass samples, and the cutting speed of 194 mm/s and the maximum edge collapse of less than 132 μm are realized.

Validation of tool mark analysis of cut costal cartilage.

PubMed

Love, Jennifer C; Derrick, Sharon M; Wiersema, Jason M; Peters, Charles

2012-03-01

This study was designed to establish the potential error rate associated with the generally accepted method of tool mark analysis of cut marks in costal cartilage. Three knives with different blade types were used to make experimental cut marks in costal cartilage of pigs. Each cut surface was cast, and each cast was examined by three analysts working independently. The presence of striations, regularity of striations, and presence of a primary and secondary striation pattern were recorded for each cast. The distance between each striation was measured. The results showed that striations were not consistently impressed on the cut surface by the blade's cutting edge. Also, blade type classification by the presence or absence of striations led to a 65% misclassification rate. Use of the classification tree and cross-validation methods and inclusion of the mean interstriation distance decreased the error rate to c. 50%. © 2011 American Academy of Forensic Sciences.

[Scanning electron microscopic investigations of cutting edge quality in lamellar keratotomy using the Wavelight femtosecond laser (FS-200) : What influence do spot distance and an additional tunnel have?

PubMed

Hammer, T; Höche, T; Heichel, J

2018-01-01

Femtosecond lasers (fs-lasers) are established cutting instruments for the creation of LASIK flaps. Previous studies often showed even rougher surfaces after application of fs-laser systems compared to lamellar keratotomy with mechanical microkeratomes. When cutting the cornea with fs-lasers, an intrastromal gas development occurs, which has a potentially negative influence on the cutting quality if the gas cannot be dissipated; therefore, manufacturers have chosen the way of gas assimilation in so-called pockets. The investigated system creates a tunnel which opens under the conjunctiva. The aim of this study was to investigate the effects of a tunnel as well as the influence of different spot distances on the quality of cut surfaces and edges. In this experimental study on freshly enucleated porcine eyes (n = 15), the following cuts were carried out with the FS-200 (Wavelight, Erlangen, Germany): 1. standard setting (spot and line separation 8 µm), 2. with tunnel for gas drainage, 3. without gas-conducting tunnel, 4. with increased spot spacing (spot and line separation 9 μm instead of 8 μm) and 5. with reduced spot spacing (spot and line separation 7 μm instead of 8 μm). Subsequently, scanning electron microscopy (FEI Quanta 650, Hillsboro, OR) of the cut edges and surfaces as well as the gas drain tunnel were performed. The evaluation was based on an established score. The current fs-laser system (200 Hz) is able to create smooth cutting surfaces and sharp edges. The changed density of laser pulses compared to the standard settings with a reduced or increased distance between the pulses, did not achieve any further improvement in the surface quality. The gas-conducting tunnel could be detected by scanning electron microscope. In the case of cutting without a tunnel, roughened surfaces and irregularities on the cutting edges were found. When the FS-200 fs-laser is used, LASIK cuts with very smooth cut surfaces and sharp cutting edges are achieved. This is only valid as long as an additional tunnel with the fs-laser is placed under the conjunctiva. It can be assumed that the resulting gas is effectively drained through this tunnel. The installation of the tunnel represents a new possibility to replace previous techniques of gas assimilation in deeper lying cutting areas.

Work with Us | Research Site Name | NREL

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ullamco laboris nisi ut aliquip ex ea commodo consequat. Hero Image - Width of 1746px - Height can vary ex ea commodo consequat. Learn about our technology partnership agreements. Use our cutting-edge commercialization programs. Join Our Team Find an opportunity: Job | Internship | Post Doc | Director's Postdoctoral

Physical Chemistry in Practice: Evaluation of DVD Modules

ERIC Educational Resources Information Center

Dyer, James U.; Towns, Marcy; Weaver, Gabriela C.

2007-01-01

The Physical Chemistry in Practice (PCIP) DVD contains video programs (modules) and experimental data that present the research of scientists working in applications of physical chemistry. The DVD allows students to learn about cutting edge research in physical chemistry while making connections to the theoretical concepts learned in lecture.…

Not Getting Along?

ERIC Educational Resources Information Center

Adams, Caralee

2007-01-01

Crafting a positive school work environment takes time and will that many educators often lack. Yet some experts say that how the principal, teachers, and staff get along is paramount to parental involvement and to cutting-edge instruction. Unfortunately, according to this author, the workplace culture in many schools is undeniably dysfunctional.…

Work with Us | Hydrogen and Fuel Cells | NREL

Science.gov Websites

agreements. Use our cutting-edge research facilities to develop, test, and evaluate hydrogen and fuel cell science behind emerging hydrogen and fuel cell technologies and develop, test, and validate new for qualified partners to participate in cooperative research and development agreement (CRADA

Advertising to Children: Concepts and Controversies.

ERIC Educational Resources Information Center

Macklin, M. Carole, Ed.; Carlson, Les, Ed.

This book presents cutting-edge research designed to stimulate and inform the debate over advertising to the children's market and the effects such advertising has on children. Perspectives are organized in sections to address what children know and think about advertising, how advertising works with children, and what issues are at the forefront…

Vocabulary Instruction for Struggling Students. What Works for Special-Needs Learners Series

ERIC Educational Resources Information Center

Vadasy, Patricia F.; Nelson, J. Ron

2012-01-01

Addressing a key skill in reading, writing, and speaking, this comprehensive book is grounded in cutting-edge research on vocabulary development. It presents evidence-based instructional approaches for at-risk students, including English language learners and those with learning difficulties. Coverage ranges from storybook reading interventions…

Toward a first-principles integrated simulation of tokamak edge plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, C S; Klasky, Scott A; Cummings, Julian

2008-01-01

Performance of the ITER is anticipated to be highly sensitive to the edge plasma condition. The edge pedestal in ITER needs to be predicted from an integrated simulation of the necessary firstprinciples, multi-scale physics codes. The mission of the SciDAC Fusion Simulation Project (FSP) Prototype Center for Plasma Edge Simulation (CPES) is to deliver such a code integration framework by (1) building new kinetic codes XGC0 and XGC1, which can simulate the edge pedestal buildup; (2) using and improving the existing MHD codes ELITE, M3D-OMP, M3D-MPP and NIMROD, for study of large-scale edge instabilities called Edge Localized Modes (ELMs); andmore » (3) integrating the codes into a framework using cutting-edge computer science technology. Collaborative effort among physics, computer science, and applied mathematics within CPES has created the first working version of the End-to-end Framework for Fusion Integrated Simulation (EFFIS), which can be used to study the pedestal-ELM cycles.« less

Influence of Surface Features for Increased Heat Dissipation on Tool Wear

PubMed Central

Beno, Tomas; Hoier, Philipp; Wretland, Anders

2018-01-01

The critical problems faced during the machining process of heat resistant superalloys, (HRSA), is the concentration of heat in the cutting zone and the difficulty in dissipating it. The concentrated heat in the cutting zone has a negative influence on the tool life and surface quality of the machined surface, which in turn, contributes to higher manufacturing costs. This paper investigates improved heat dissipation from the cutting zone on the tool wear through surface features on the cutting tools. Firstly, the objective was to increase the available surface area in high temperature regions of the cutting tool. Secondly, multiple surface features were fabricated for the purpose of acting as channels in the rake face to create better access for the coolant to the proximity of the cutting edge. The purpose was thereby to improve the cooling of the cutting edge itself, which exhibits the highest temperature during machining. These modified inserts were experimentally investigated in face turning of Alloy 718 with high-pressure coolant. Overall results exhibited that surface featured inserts decreased flank wear, abrasion of the flank face, cutting edge deterioration and crater wear probably due to better heat dissipation from the cutting zone. PMID:29693579

Simultaneous laser cutting and welding of metal foil to edge of a plate

DOEpatents

Pernicka, John C.; Benson, David K.; Tracy, C. Edwin

1996-01-01

A method of welding an ultra-thin foil to the edge of a thicker sheet to form a vacuum insulation panel comprising the steps of providing an ultra-thin foil having a thickness less than 0.002, providing a top plate having an edge and a bottom plate having an edge, clamping the foil to the edge of the plate wherein the clamps act as heat sinks to distribute heat through the foil, providing a laser, moving the laser relative to the foil and the plate edges to form overlapping weld beads to weld the foil to the plate edges while simultaneously cutting the foil along the weld line formed by the overlapping beads.

Maintaining knife sharpness in industrial meat cutting: A matter of knife or meat cutter ability.

PubMed

Karltun, J; Vogel, K; Bergstrand, M; Eklund, J

2016-09-01

Knife sharpness is imperative in meat cutting. The aim of this study was to compare the impact of knife blade steel quality with meat cutters' individual ability to maintain the cutting edge sharp in an industrial production setting. Twelve meat cutters in two different companies using three different knives during normal production were studied in this quasi-experimental study. Methods included were measuring knife cutting force before and after knife use, time knives were used, ratings of sharpness and discomfort and interviews. Results showed that the meat cutters' skill of maintaining sharpness during work had a much larger effect on knife sharpness during work than the knife steel differences. The ability was also related to feelings of discomfort and to physical exertion. It was found that meat cutters using more knives were more likely to suffer from discomfort in the upper limbs, which is a risk for developing MSD. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Built-Up Edge Formation during Stable State of Wear in AISI 304 Stainless Steel on Machining Performance and Surface Integrity of the Machined Part.

PubMed

Ahmed, Yassmin Seid; Fox-Rabinovich, German; Paiva, Jose Mario; Wagg, Terry; Veldhuis, Stephen Clarence

2017-10-25

During machining of stainless steels at low cutting -speeds, workpiece material tends to adhere to the cutting tool at the tool-chip interface, forming built-up edge (BUE). BUE has a great importance in machining processes; it can significantly modify the phenomenon in the cutting zone, directly affecting the workpiece surface integrity, cutting tool forces, and chip formation. The American Iron and Steel Institute (AISI) 304 stainless steel has a high tendency to form an unstable BUE, leading to deterioration of the surface quality. Therefore, it is necessary to understand the nature of the surface integrity induced during machining operations. Although many reports have been published on the effect of tool wear during machining of AISI 304 stainless steel on surface integrity, studies on the influence of the BUE phenomenon in the stable state of wear have not been investigated so far. The main goal of the present work is to investigate the close link between the BUE formation, surface integrity and cutting forces in the stable sate of wear for uncoated cutting tool during the cutting tests of AISI 304 stainless steel. The cutting parameters were chosen to induce BUE formation during machining. X-ray diffraction (XRD) method was used for measuring superficial residual stresses of the machined surface through the stable state of wear in the cutting and feed directions. In addition, surface roughness of the machined surface was investigated using the Alicona microscope and Scanning Electron Microscopy (SEM) was used to reveal the surface distortions created during the cutting process, combined with chip undersurface analyses. The investigated BUE formation during the stable state of wear showed that the BUE can cause a significant improvement in the surface integrity and cutting forces. Moreover, it can be used to compensate for tool wear through changing the tool geometry, leading to the protection of the cutting tool from wear.

Effect of Built-Up Edge Formation during Stable State of Wear in AISI 304 Stainless Steel on Machining Performance and Surface Integrity of the Machined Part

PubMed Central

Fox-Rabinovich, German; Wagg, Terry

2017-01-01

During machining of stainless steels at low cutting -speeds, workpiece material tends to adhere to the cutting tool at the tool–chip interface, forming built-up edge (BUE). BUE has a great importance in machining processes; it can significantly modify the phenomenon in the cutting zone, directly affecting the workpiece surface integrity, cutting tool forces, and chip formation. The American Iron and Steel Institute (AISI) 304 stainless steel has a high tendency to form an unstable BUE, leading to deterioration of the surface quality. Therefore, it is necessary to understand the nature of the surface integrity induced during machining operations. Although many reports have been published on the effect of tool wear during machining of AISI 304 stainless steel on surface integrity, studies on the influence of the BUE phenomenon in the stable state of wear have not been investigated so far. The main goal of the present work is to investigate the close link between the BUE formation, surface integrity and cutting forces in the stable sate of wear for uncoated cutting tool during the cutting tests of AISI 304 stainless steel. The cutting parameters were chosen to induce BUE formation during machining. X-ray diffraction (XRD) method was used for measuring superficial residual stresses of the machined surface through the stable state of wear in the cutting and feed directions. In addition, surface roughness of the machined surface was investigated using the Alicona microscope and Scanning Electron Microscopy (SEM) was used to reveal the surface distortions created during the cutting process, combined with chip undersurface analyses. The investigated BUE formation during the stable state of wear showed that the BUE can cause a significant improvement in the surface integrity and cutting forces. Moreover, it can be used to compensate for tool wear through changing the tool geometry, leading to the protection of the cutting tool from wear. PMID:29068405

A next generation processing system for edging and trimming

Treesearch

A. Lynn Abbott; Daniel L. Schmoldt; Philip A. Araman

2000-01-01

This paper describes a prototype scanning system that is being developed for the processing of rough hardwood lumber. The overall goal of the system is to automate the selection of cutting positions for the edges and ends of rough, green lumber. Such edge and trim cuts are typically performed at sawmills in an effort to increase board value prior to sale, and this...

Laser beam machining of polycrystalline diamond for cutting tool manufacturing

NASA Astrophysics Data System (ADS)

Wyszyński, Dominik; Ostrowski, Robert; Zwolak, Marek; Bryk, Witold

2017-10-01

The paper concerns application of DPSS Nd: YAG 532nm pulse laser source for machining of polycrystalline WC based diamond inserts (PCD). The goal of the research was to determine optimal laser cutting parameters for cutting tool shaping. Basic criteria to reach the goal was cutting edge quality (minimalization of finishing operations), material removal rate (time and cost efficiency), choice of laser beam characteristics (polarization, power, focused beam diameter). The research was planned and realised and analysed according to design of experiment rules (DOE). The analysis of the cutting edge was prepared with use of Alicona Infinite Focus measurement system.

Analyzing the effect of tool edge radius on cutting temperature in micro-milling process

NASA Astrophysics Data System (ADS)

Liang, Y. C.; Yang, K.; Zheng, K. N.; Bai, Q. S.; Chen, W. Q.; Sun, G. Y.

2010-10-01

Cutting heat is one of the important physical subjects in the cutting process. Cutting heat together with cutting temperature produced by the cutting process will directly have effects on the tool wear and the life as well as on the workpiece processing precision and surface quality. The feature size of the workpiece is usually several microns. Thus, the tiny changes of cutting temperature will affect the workpiece on the surface quality and accuracy. Therefore, cutting heat and temperature generated in micro-milling will have significantly different effect than the one in the traditional tools cutting. In this paper, a two-dimensional coupled thermal-mechanical finite element model is adopted to determine thermal fields and cutting temperature during the Micro-milling process, by using software Deform-2D. The effect of tool edge radius on effective stress, effective strain, velocity field and cutting temperature distribution in micro-milling of aluminum alloy Al2024-T6 were investigated and analyzed. Also, the transient cutting temperature distribution was simulated dynamically. The simulation results show that the cutting temperature in Micro-milling is lower than those occurring in conventional milling processes due to the small loads and low cutting velocity. With increase of tool edge radius, the maximum temperature region gradually occurs on the contact region between finished surfaced and flank face of micro-cutter, instead of the rake face or the corner of micro-cutter. And this phenomenon shows an obvious size effect.

The cutting edge - Micro-CT for quantitative toolmark analysis of sharp force trauma to bone.

PubMed

Norman, D G; Watson, D G; Burnett, B; Fenne, P M; Williams, M A

2018-02-01

Toolmark analysis involves examining marks created on an object to identify the likely tool responsible for creating those marks (e.g., a knife). Although a potentially powerful forensic tool, knife mark analysis is still in its infancy and the validation of imaging techniques as well as quantitative approaches is ongoing. This study builds on previous work by simulating real-world stabbings experimentally and statistically exploring quantitative toolmark properties, such as cut mark angle captured by micro-CT imaging, to predict the knife responsible. In Experiment 1 a mechanical stab rig and two knives were used to create 14 knife cut marks on dry pig ribs. The toolmarks were laser and micro-CT scanned to allow for quantitative measurements of numerous toolmark properties. The findings from Experiment 1 demonstrated that both knives produced statistically different cut mark widths, wall angle and shapes. Experiment 2 examined knife marks created on fleshed pig torsos with conditions designed to better simulate real-world stabbings. Eight knives were used to generate 64 incision cut marks that were also micro-CT scanned. Statistical exploration of these cut marks suggested that knife type, serrated or plain, can be predicted from cut mark width and wall angle. Preliminary results suggest that knives type can be predicted from cut mark width, and that knife edge thickness correlates with cut mark width. An additional 16 cut marks walls were imaged for striation marks using scanning electron microscopy with results suggesting that this approach might not be useful for knife mark analysis. Results also indicated that observer judgements of cut mark shape were more consistent when rated from micro-CT images than light microscopy images. The potential to combine micro-CT data, medical grade CT data and photographs to develop highly realistic virtual models for visualisation and 3D printing is also demonstrated. This is the first study to statistically explore simulated real-world knife marks imaged by micro-CT to demonstrate the potential of quantitative approaches in knife mark analysis. Findings and methods presented in this study are relevant to both forensic toolmark researchers as well as practitioners. Limitations of the experimental methodologies and imaging techniques are discussed, and further work is recommended. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of alternative snow plow cutting edges.

DOT National Transportation Integrated Search

2009-05-01

With approximately 450 snow plow trucks, the Maine Department of Transportation (MaineDOT) uses in : excess of 10,000 linear feet of plow cutting edges each winter season. Using the 2008-2009 cost per linear : foot of $48.32, the Departments total co...

"Meniscus Sign" to Identify the Lenticule Edge in Small-Incision Lenticule Extraction.

PubMed

Titiyal, Jeewan S; Kaur, Manpreet; Brar, Anand S; Falera, Ruchita

2018-06-01

To describe our technique of lenticule edge identification in small-incision lenticule extraction using the "meniscus sign" to prevent lenticule misdissection. Femtosecond laser application for small-incision lenticule extraction was performed. A "double ring" was visible, signifying the edge of the cap cut (outer ring) and lenticule cut (inner ring). The anterior and posterior lamellar planes were delineated in 2 different directions. During creation of the posterior lamellar channel, the lenticule edge was slightly pushed away from the surgeon to create a gap between the inner ring (diameter of the lenticule cut) and the lenticule edge. The lenticule edge assumed a frilled wavy appearance, and the meniscus sign was observed as a gap between the lenticule edge and the inner ring. The meniscus-shaped gap served as a landmark to identify the lenticule edge, and the relationship between the frilled lenticule edge and surgical instruments further acted as a guide to identify the correct plane of dissection. This technique was successfully undertaken in 50 eyes of 25 patients. The meniscus sign was observed in all cases, and no case had cap lenticular adhesions. The meniscus sign helps to identify the lenticule edge and correct dissection planes and provides a visual landmark during the entire surgical procedure.

CO2 laser cutting of ultra thin (75 μm) glass based rigid optical solar reflector (OSR) for spacecraft application

NASA Astrophysics Data System (ADS)

Mishra, Shubham; Sridhara, N.; Mitra, Avijit; Yougandar, B.; Dash, Sarat Kumar; Agarwal, Sanjay; Dey, Arjun

2017-03-01

Present study reports for the first time laser cutting of multilayered coatings on both side of ultra thin (i.e., 75 μm) glass substrate based rigid optical solar reflector (OSR) for spacecraft thermal control application. The optimization of cutting parameters was carried out as a function of laser power, cutting speed and number of cutting passes and their effect on cutting edge quality. Systematic and in-detail microstructural characterizations were carried out by optical and scanning electron microscopy techniques to study the laser affected zone and cutting edge quality. Sheet resistance and water contact angle experiments were also conducted locally both prior and after laser cut to investigate the changes of electrical and surface properties, if any.

Surface topography and roughness of high-speed milled AlMn1Cu

NASA Astrophysics Data System (ADS)

Wang, Zhenhua; Yuan, Juntang; Yin, Zengbin; Hu, Xiaoqiu

2016-10-01

The aluminum alloy AlMn1Cu has been broadly applied for functional parts production because of its good properties. But few researches about the machining mechanism and the surface roughness were reported. The high-speed milling experiments are carried out in order to improve the machining quality and reveal the machining mechanism. The typical topography features of machined surface are observed by scan electron microscope(SEM). The results show that the milled surface topography is mainly characterized by the plastic shearing deformation surface and material piling zone. The material flows plastically along the end cutting edge of the flat-end milling tool and meanwhile is extruded by the end cutting edge, resulting in that materials partly adhere to the machined surface and form the material piling zone. As the depth of cut and the feed per tooth increase, the plastic flow of materials is strengthened and the machined surface becomes rougher. However, as the cutting speed increases, the plastic flow of materials is weakened and the milled surface becomes smoother. The cutting parameters (e.g. cutting speed, feed per tooth and depth of cut) influencing the surface roughness are analyzed. It can be concluded that the roughness of the machined surface formed by the end cutting edge is less than that by the cylindrical cutting edge when a cylindrical flat-end mill tool is used for milling. The proposed research provides the typical topography features of machined surface of the anti-rust aluminum alloy AlMn1Cu in high speed milling.

The sensitivity of tokamak magnetohydrodynamics stability on the edge equilibrium

NASA Astrophysics Data System (ADS)

Zheng, L. J.; Kotschenreuther, M. T.; Valanju, P.

2017-10-01

Due to the X-point singularity, the safety factor tends to infinity as approaching to the last closed flux surface. The numerical treatments of the near X-point behavior become challenging both for equilibrium and stability. The usual solution is to cut off a small fraction of edge region for system stability evaluation or simply use an up-down symmetric equilibrium without X-point as an approximation. In this work, we assess the sensitivity of this type of equilibrium treatments on the stability calculation. It is found that the system stability can depend strongly on the safety factor value (qa) at the edge after the cutting-off. When the edge safety factor value falls in the vicinity of a rational mode number (referred to as the resonant gap), the system becomes quite unstable due to the excitation of the peeling type modes. Instead, when the edge safety factor is outside the resonant gaps, the system is much more stable and the predominant modes become the usual external kink (or ballooning and infernal) type. It is also found that the resonant gaps become smaller and smaller as qa increases. The ideal magnetohydrodynamic peeling ballooning stability diagram is widely used to explain the experimental observations, and the current results indicate that the conventional peeling ballooning stability diagram based on the simplified equilibrium needs to be reexamined.

An Online, Interactive Renewable Energy Laboratory

ERIC Educational Resources Information Center

O'Leary, D. A.; Shattuck, J.; Kubby, J.

2012-01-01

An undergraduate introductory science, technology, engineering, and math (STEM) class can be a jarring disappointment to new students expecting to work with cutting-edge, real-world technology. Their cell phones are often more technically advanced and real-world than the tools used in a class lab. Not surprisingly, many complain that the STEM labs…

An American Sophist: The Surprising Career of Stanley Fish

ERIC Educational Resources Information Center

Rothman, David J.

2008-01-01

From literary theorist to university administrator to "New York Times" blogger and social critic, Stanley Fish has risen from simple beginnings as a specialist in English Renaissance poetry to ride the ideological foam of all things cutting edge. David Rothman examines the provocative ideas behind the life's work of one of the academy's most…

Defense Threat Reduction Agency > About > Media > News > News Archive

Science.gov Websites

into pulmonary research -- DTRA's ATHENA developing cutting-edge technology that benefits soldiers and civilians Dec 15 - Germany to fund more surveillance along Tunisia-Libya border -- DTRA project aims to help 27 - Modern border facility opens thanks to US support -- DTRA working with Georgian Ministry of

Synchronizing with the Current Technology Trends

ERIC Educational Resources Information Center

Gupta, Sanjay; Gupta, Archana

2005-01-01

Software professionals have to synchronize themselves with the new cutting edge technologies or they may be phased out of their work. They can opt this through in-house training by an instructor, by attending a course at a training institute after office hours, or by taking up an online course. This article provides an analysis of the…

3 CFR 8730 - Proclamation 8730 of October 6, 2011. National Energy Action Month, 2011

Code of Federal Regulations, 2012 CFR

2012-01-01

... cutting-edge technologies, creating new American jobs and industries, and putting us on track to doubling..., and entrepreneurs are working together to move new ideas and technologies from the lab to the... economy, and a healthier environment for our children. IN WITNESS WHEREOF, I have hereunto set my hand...

Community Learning Campus: The Hard Work Begins after the Ribbon-Cutting

ERIC Educational Resources Information Center

Education Canada, 2012

2012-01-01

Dorothy Negropontes was a key player in the creation of the Community Learning Campus (CLC), an innovative collaboration of education and community leaders in Olds, Alberta. A former Assistant Superintendent with Chinook's Edge School District, she co-chaired the steering committee that developed the project, served as its executive director…

The Next Steps in Our Understanding of Gene-Peer Interplay: A Commentary

ERIC Educational Resources Information Center

Burt, S. Alexandra

2014-01-01

The studies included in this special issue on gene-peer interplay in child and adolescent outcomes can uniformly be described as cutting edge and methodologically sophisticated. When viewed together, they all but conclusively document the presence and importance of gene-peer interplay in child and adolescent outcomes. Nevertheless, more work on…

The Scientification of Skin Whitening and the Entrepreneurial University-Linked Corporate Scientific Officer

ERIC Educational Resources Information Center

Mire, Amina

2012-01-01

This work examines the interlocking strategies of scientific entrepreneurialism and academic capitalism in cutting-edge innovations in molecular biology, biomedicine, and other life sciences deployed in research and the development of high-end skin whitening and anti-aging cosmeceuticals. Skin whitening products and anti-aging cosmeceuticals are…

College Mental Health at the Cutting Edge?

ERIC Educational Resources Information Center

Schwartz, Victor

2013-01-01

As someone who has been involved in college mental health in three different roles, the author would say those who work in this field inhabit a strange space. College mental health centers are generally seen as somewhat peripheral to the core mission of universities by upper administration. Counseling centers do not reside within academic…

New Directions for Self-Regulation of Learning in Postsecondary Education

ERIC Educational Resources Information Center

Bembenutty, Hefer

2011-01-01

This chapter highlights the major contributions of this volume on self-regulation of learning and provides new directions for cutting-edge theoretical and empirical work that could serve to facilitate self-regulation of learning in postsecondary education. "Self-regulation of learning" refers to learners' beliefs about their ability to engage in…

The Cutting Edge of Fun: Making Work Play at the New American School

ERIC Educational Resources Information Center

Sims, Christopher Otter

2012-01-01

This dissertation presents an ethnographic account of the launch of "The Downtown School for Design, Media, and Technology," one of the most prominent American school reform projects in recent years. Drawing on popular accounts about children and young people's pervasive affinity for digital media, and especially video games, the…

Variable diameter CO₂ laser ring-cutting system adapted to a zoom microscope for applications on polymer tapes.

PubMed

Förster, Erik; Bohnert, Patrick; Kraus, Matthias; Kilper, Roland; Müller, Ute; Buchmann, Martin; Brunner, Robert

2016-11-20

This paper presents the conception and implementation of a variable diameter ring-cutting system for a CO₂ laser with a working wavelength of 10.6 μm. The laser-cutting system is adapted to an observation zoom microscope for combined use and is applicable for the extraction of small circular areas from polymer films, such as forensic adhesive tapes in a single shot. As an important characteristic for our application, the variable diameter ring-cutting system provides telecentricity in the target area. Ring diameters are continuously tunable between 500 μm and 2 mm. A minimum width of less than 20 μm was found for the ring profile edge. The basic characteristics of the system, including telecentricity, were experimentally evaluated and demonstrated by cutting experiments on different polymer tapes and further exemplary samples.

Simultaneous laser cutting and welding of metal foil to edge of a plate

DOEpatents

Pernicka, J.C.; Benson, D.K.; Tracy, C.E.

1996-03-19

A method is described for welding an ultra-thin foil to the edge of a thicker sheet to form a vacuum insulation panel comprising the steps of providing an ultra-thin foil having a thickness less than 0.002, providing a top plate having an edge and a bottom plate having an edge, clamping the foil to the edge of the plate wherein the clamps act as heat sinks to distribute heat through the foil, providing a laser, moving the laser relative to the foil and the plate edges to form overlapping weld beads to weld the foil to the plate edges while simultaneously cutting the foil along the weld line formed by the overlapping beads. 7 figs.

Preset pivotal tool holder

DOEpatents

Asmanes, Charles

1979-01-01

A tool fixture is provided for precise pre-alignment of a radiused edge cutting tool in a tool holder relative to a fixed reference pivot point established on said holder about which the tool holder may be selectively pivoted relative to the fixture base member to change the contact point of the tool cutting edge with a workpiece while maintaining the precise same tool cutting radius relative to the reference pivot point.

Cut marks on bone surfaces: influences on variation in the form of traces of ancient behaviour

PubMed Central

Braun, David R.; Pante, Michael; Archer, William

2016-01-01

Although we know that our lineage has been producing sharp-edged tools for over 2.6 Myr, our knowledge of what they were doing with these tools is far less complete. Studies of these sharp-edged stone tools show that they were most probably used as cutting implements. However, the only substantial evidence of this is the presence of cut marks on the bones of animals found in association with stone tools in ancient deposits. Numerous studies have aimed to quantify the frequency and placement of these marks. At present there is little consensus on the meaning of these marks and how the frequency relates to specific behaviours in the past. Here we investigate the possibility that mechanical properties associated with edges of stone tools as well as the properties of bones themselves may contribute to the overall morphology of these marks and ultimately their placement in the archaeological record. Standardized tests of rock mechanics (Young's modulus and Vickers hardness) indicate that the hardness of tool edges significantly affects cut-mark morphology. In addition, we show that indentation hardness of bones also impacts the overall morphology of cut marks. Our results show that rock type and bone portions influence the shape and prevalence of cut marks on animal bones. PMID:27274806

Edge-entanglement spectrum correspondence in a nonchiral topological phase and Kramers-Wannier duality

NASA Astrophysics Data System (ADS)

Ho, Wen Wei; Cincio, Lukasz; Moradi, Heidar; Gaiotto, Davide; Vidal, Guifre

2015-03-01

In a system with chiral topological order, there is a remarkable correspondence between the edge and entanglement spectra: the low-energy spectrum of the system in the presence of a physical edge coincides with the lowest part of the entanglement spectrum (ES) across a virtual cut of the system into two parts, up to rescaling and shifting. This correspondence is believed to be due to the existence of protected gapless edge modes. In this paper, we explore whether the edge-entanglement spectrum correspondence extends to nonchiral topological phases, where there are no protected gapless edge modes. Specifically, we consider the Wen-plaquette model, which is equivalent to the Kitaev toric code model and has Z2 topological order (quantum double of Z2) . The unperturbed Wen-plaquette model displays an exact correspondence: both the edge and entanglement spectra within each topological sector a (a =1 ,⋯,4 ) are flat and equally degenerate. Here, we show, through a detailed microscopic calculation, that in the presence of generic local perturbations: (i) the effective degrees of freedom for both the physical edge and the entanglement cut consist of a (spin-1 /2 ) spin chain, with effective Hamiltonians Hedgea and Henta, respectively, both of which have a Z2 symmetry enforced by the bulk topological order; (ii) there is in general no match between the low-energy spectra of Hedgea and Henta, that is, there is no edge-ES correspondence. However, if supplement the Z2 topological order with a global symmetry (translational invariance along the edge/entanglement cut), i.e., by considering the Wen-plaquette model as a symmetry-enriched topological phase (SET), then there is a finite domain in Hamiltonian space in which both Hedgea and Henta realize the critical Ising model, whose low-energy effective theory is the c =1 /2 Ising CFT. This is achieved because the presence of the global symmetry implies that the effective degrees of freedom of both the edge and entanglement cut are governed by Kramers-Wannier self-dual Hamiltonians, in addition to them being Z2 symmetric, which is imposed by the topological order. Thus, by considering the Wen-plaquette model as a SET, the topological order in the bulk together with the translation invariance of the perturbations along the edge/cut imply an edge-ES correspondence at least in some finite domain in Hamiltonian space.

Thin edge-defined film-fed growth (EFG) octagons

NASA Astrophysics Data System (ADS)

Kalejs, J. P.

1992-03-01

Mobil Solar Energy Corp. investigated manufacturing crystalline silicon wafers using the edge-defined film-fed growth (EFG) technique. This report identifies the following: (1) current capabilities for manufacturing 200-micron-thick crystalline silicon wafers (10 cm x 10 cm) produced by growing octagons using the EFG technique and laser cutting them into wafers; (2) potential manufacturing improvements from decreasing the thickness of the wafers, improving the quality of the laser cut edge, and increasing cutting speed, all of which lead to reduce manufacturing costs, improved performance, and increased production capacities; (3) problems that impede achieving these potentials; and (4) costs and other requirements involved in overcoming the problems.

Micromachined cutting blade formed from {211}-oriented silicon

DOEpatents

Fleming, James G.; Sniegowski, Jeffry J.; Montague, Stephen

2003-09-09

A cutting blade is disclosed fabricated of micromachined silicon. The cutting blade utilizes a monocrystalline silicon substrate having a {211} crystalline orientation to form one or more cutting edges that are defined by the intersection of {211} crystalline planes of silicon with {111} crystalline planes of silicon. This results in a cutting blade which has a shallow cutting-edge angle .theta. of 19.5.degree.. The micromachined cutting blade can be formed using an anisotropic wet etching process which substantially terminates etching upon reaching the {111} crystalline planes of silicon. This allows multiple blades to be batch fabricated on a common substrate and separated for packaging and use. The micromachined cutting blade, which can be mounted to a handle in tension and optionally coated for increased wear resistance and biocompatibility, has multiple applications including eye surgery (LASIK procedure).

Micromachined cutting blade formed from {211}-oriented silicon

DOEpatents

Fleming, James G [Albuquerque, NM; Fleming, legal representative, Carol; Sniegowski, Jeffry J [Tijeras, NM; Montague, Stephen [Albuquerque, NM

2011-08-09

A cutting blade is disclosed fabricated of micromachined silicon. The cutting blade utilizes a monocrystalline silicon substrate having a {211} crystalline orientation to form one or more cutting edges that are defined by the intersection of {211} crystalline planes of silicon with {111} crystalline planes of silicon. This results in a cutting blade which has a shallow cutting-edge angle .theta. of 19.5.degree.. The micromachined cutting blade can be formed using an anisotropic wet etching process which substantially terminates etching upon reaching the {111} crystalline planes of silicon. This allows multiple blades to be batch fabricated on a common substrate and separated for packaging and use. The micromachined cutting blade, which can be mounted to a handle in tension and optionally coated for increased wear resistance and biocompatibility, has multiple applications including eye surgery (LASIK procedure).

Effects of Different Polarization Strategies on Laser Cutting with Direct Diode Lasers

NASA Astrophysics Data System (ADS)

Rodrigues, G. Costa; Duflou, J. R.

As Direct Diode Lasers are introduced as an emerging technology for laser cutting of metal sheets, new challenges arise. The relatively low beam quality remains a limitation to the maximum cutting speed. One way to balance this may be a strategic use of laser polarization in order to influence laser material interaction in the cutting kerf. In this paper the effects of cross-, linear-, radial- and azimuthal- laser beam polarization arrangements are studied with both Fusion and Flame cutting at an output power of approximately 750W. Different combinations of materials and thicknesses were cut and the maximum cutting speed and edge quality analyzed. It is found that at similar cutting edge quality, improvements in cutting speed can go up to 40% with an inert gas, such as Nitrogen, and up to 20% with a reactive gas, such as Oxygen, in agreement with analytical models for absorption previously developed by the authors.

National Institute of Environmental Health Sciences: 50 Years of Advancing Science and Improving Lung Health.

PubMed

Antony, Veena B; Redlich, Carrie A; Pinkerton, Kent E; Balmes, John; Harkema, Jack R

2016-11-15

The American Thoracic Society celebrates the 50th anniversary of the National Institute of Environmental Health Sciences (NIEHS). The NIEHS has had enormous impact through its focus on research, training, and translational science on lung health. It has been an advocate for clean air both in the United States and across the world. The cutting-edge science funded by the NIEHS has led to major discoveries that have broadened our understanding of the pathogenesis and treatment for lung disease. Importantly, the NIEHS has developed and fostered mechanisms that require cross-cutting science across the spectrum of areas of inquiry, bringing together environmental and social scientists with clinicians to bring their expertise on specific areas of investigation. The intramural program of the NIEHS nurtures cutting-edge science, and the extramural program encourages investigator-initiated research while at the same time providing broader direction through important initiatives. Under the umbrella of the NIEHS and guided by Dr. Linda Birnbaum, the director of the NIEHS, important collaborative programs, such as the Superfund Program and the National Toxicology Program, work to discover mechanisms to protect from environmental toxins. The American Thoracic Society has overlapping goals with the NIEHS, and the strategic plans of both august bodies converge to synergize on population lung health. These bonds must be tightened and highlighted as we work toward our common goals.

The Seasonal Dynamics of Artificial Nest Predation Rates along Edges in a Mosaic Managed Reedbed.

PubMed

Malzer, Iain; Helm, Barbara

2015-01-01

Boundaries between different habitats can be responsible for changes in species interactions, including modified rates of encounter between predators and prey. Such 'edge effects' have been reported in nesting birds, where nest predation rates can be increased at habitat edges. The literature concerning edge effects on nest predation rates reveals a wide variation in results, even within single habitats, suggesting edge effects are not fixed, but dynamic throughout space and time. This study demonstrates the importance of considering dynamic mechanisms underlying edge effects and their relevance when undertaking habitat management. In reedbed habitats, management in the form of mosaic winter reed cutting can create extensive edges which change rapidly with reed regrowth during spring. We investigate the seasonal dynamics of reedbed edges using an artificial nest experiment based on the breeding biology of a reedbed specialist. We first demonstrate that nest predation decreases with increasing distance from the edge of cut reed blocks, suggesting edge effects have a pivotal role in this system. Using repeats throughout the breeding season we then confirm that nest predation rates are temporally dynamic and decline with the regrowth of reed. However, effects of edges on nest predation were consistent throughout the season. These results are of practical importance when considering appropriate habitat management, suggesting that reed cutting may heighten nest predation, especially before new growth matures. They also contribute directly to an overall understanding of the dynamic processes underlying edge effects and their potential role as drivers of time-dependent habitat use.

The Cutting Edge, 1999-2000.

ERIC Educational Resources Information Center

Cutting Edge, 2000

2000-01-01

The Cutting Edge is a bimonthly newsletter of the Regional Center for Applied Technology and Training at Danville Community College (DCC) (Virginia) that provides the latest information on a wide range of issues including technology, business, employment trends, and new legislation. Articles from the first five issues discuss: (1) the July 2000…

Experimental investigation and modelling of surface roughness and resultant cutting force in hard turning of AISI H13 Steel

NASA Astrophysics Data System (ADS)

Boy, M.; Yaşar, N.; Çiftçi, İ.

2016-11-01

In recent years, turning of hardened steels has replaced grinding for finishing operations. This process is compared to grinding operations; hard turning has higher material removal rates, the possibility of greater process flexibility, lower equipment costs, and shorter setup time. CBN or ceramic cutting tools are widely used hard part machining. For successful application of hard turning, selection of suitable cutting parameters for a given cutting tool is an important step. For this purpose, an experimental investigation was conducted to determine the effects of cutting tool edge geometry, feed rate and cutting speed on surface roughness and resultant cutting force in hard turning of AISI H13 steel with ceramic cutting tools. Machining experiments were conducted in a CNC lathe based on Taguchi experimental design (L16) in different levels of cutting parameters. In the experiments, a Kistler 9257 B, three cutting force components (Fc, Ff and Fr) piezoelectric dynamometer was used to measure cutting forces. Surface roughness measurements were performed by using a Mahrsurf PS1 device. For statistical analysis, analysis of variance has been performed and mathematical model have been developed for surface roughness and resultant cutting forces. The analysis of variance results showed that the cutting edge geometry, cutting speed and feed rate were the most significant factors on resultant cutting force while the cutting edge geometry and feed rate were the most significant factor for the surface roughness. The regression analysis was applied to predict the outcomes of the experiment. The predicted values and measured values were very close to each other. Afterwards a confirmation tests were performed to make a comparison between the predicted results and the measured results. According to the confirmation test results, measured values are within the 95% confidence interval.

Quantum Max-flow/Min-cut

NASA Astrophysics Data System (ADS)

Cui, Shawn X.; Freedman, Michael H.; Sattath, Or; Stong, Richard; Minton, Greg

2016-06-01

The classical max-flow min-cut theorem describes transport through certain idealized classical networks. We consider the quantum analog for tensor networks. By associating an integral capacity to each edge and a tensor to each vertex in a flow network, we can also interpret it as a tensor network and, more specifically, as a linear map from the input space to the output space. The quantum max-flow is defined to be the maximal rank of this linear map over all choices of tensors. The quantum min-cut is defined to be the minimum product of the capacities of edges over all cuts of the tensor network. We show that unlike the classical case, the quantum max-flow=min-cut conjecture is not true in general. Under certain conditions, e.g., when the capacity on each edge is some power of a fixed integer, the quantum max-flow is proved to equal the quantum min-cut. However, concrete examples are also provided where the equality does not hold. We also found connections of quantum max-flow/min-cut with entropy of entanglement and the quantum satisfiability problem. We speculate that the phenomena revealed may be of interest both in spin systems in condensed matter and in quantum gravity.

Biofuels: What Are They and How Can They Improve Practical Work and Discussions?

ERIC Educational Resources Information Center

MacLean, Tristan

2014-01-01

This article looks at the potential of bioenergy as a replacement for fossil fuels, the cutting-edge research being undertaken by scientists, and classroom resources available for teaching this topic. There is currently a large programme of scientific research aiming to develop advanced biofuels (replenishable liquid biofuels from non-food plants,…

Class, Culture and the "Predicaments of Masculine Domination": Encountering Pierre Bourdieu

ERIC Educational Resources Information Center

Dillabough, Jo-Anne

2004-01-01

This paper seeks to outline and evaluate Pierre Bourdieu's work as it has appeared most recently in feminist studies and the field of gender and education. In particular, it suggests ways in which Bourdieu's theoretical insights could be seen to more effectively contribute to cutting edge debates in both social theory and feminist thought…

Teacher Quality 2.0: Toward a New Era in Education Reform

ERIC Educational Resources Information Center

Hess, Frederick M., Ed.; McShane, Michael Q., Ed.

2014-01-01

In "Teacher Quality 2.0," American Enterprise Institute (AEI) education experts Frederick M. Hess and Michael Q. McShane convene a diverse array of contributors to examine fruitful innovations that promise to improve teacher quality in a more strategic way. Much of the cutting-edge work in teacher quality is happening in nontraditional…

Developing Cross-Cultural Awareness in IT: Reflections of Australian and Chinese Students

ERIC Educational Resources Information Center

Venables, Anne; Tan, Grace; Miliszewska, Iwona

2013-01-01

To succeed within the increasingly global context of their work environment, today's IT professional needs to be equipped with both cutting-edge technical skills and a strong repertoire of "soft" skills. An important and often unrecognized soft skill is an appreciation of how various IT issues impact upon different peoples and what…

New York City's iZone. CRPE Working Paper #2011-1

ERIC Educational Resources Information Center

Lake, Robin; Gross, Betheny

2011-01-01

Can public schools learn to embrace innovation and employ cutting edge technology to solve students' most persistent learning problems? In 2010, New York City's Department of Education (NYCDOE) created the Innovation Zone (iZone) to try to accomplish just that. This report reflects the findings of a CRPE study of the iZone, its goals and…

Finding minimum-quotient cuts in planar graphs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, J.K.; Phillips, C.A.

Given a graph G = (V, E) where each vertex v {element_of} V is assigned a weight w(v) and each edge e {element_of} E is assigned a cost c(e), the quotient of a cut partitioning the vertices of V into sets S and {bar S} is c(S, {bar S})/min{l_brace}w(S), w(S){r_brace}, where c(S, {bar S}) is the sum of the costs of the edges crossing the cut and w(S) and w({bar S}) are the sum of the weights of the vertices in S and {bar S}, respectively. The problem of finding a cut whose quotient is minimum for a graph hasmore » in recent years attracted considerable attention, due in large part to the work of Rao and Leighton and Rao. They have shown that an algorithm (exact or approximation) for the minimum-quotient-cut problem can be used to obtain an approximation algorithm for the more famous minimumb-balanced-cut problem, which requires finding a cut (S,{bar S}) minimizing c(S,{bar S}) subject to the constraint bW {le} w(S) {le} (1 {minus} b)W, where W is the total vertex weight and b is some fixed balance in the range 0 < b {le} {1/2}. Unfortunately, the minimum-quotient-cut problem is strongly NP-hard for general graphs, and the best polynomial-time approximation algorithm known for the general problem guarantees only a cut whose quotient is at mostO(lg n) times optimal, where n is the size of the graph. However, for planar graphs, the minimum-quotient-cut problem appears more tractable, as Rao has developed several efficient approximation algorithms for the planar version of the problem capable of finding a cut whose quotient is at most some constant times optimal. In this paper, we improve Rao`s algorithms, both in terms of accuracy and speed. As our first result, we present two pseudopolynomial-time exact algorithms for the planar minimum-quotient-cut problem. As Rao`s most accurate approximation algorithm for the problem -- also a pseudopolynomial-time algorithm -- guarantees only a 1.5-times-optimal cut, our algorithms represent a significant advance.« less

Finding minimum-quotient cuts in planar graphs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, J.K.; Phillips, C.A.

Given a graph G = (V, E) where each vertex v [element of] V is assigned a weight w(v) and each edge e [element of] E is assigned a cost c(e), the quotient of a cut partitioning the vertices of V into sets S and [bar S] is c(S, [bar S])/min[l brace]w(S), w(S)[r brace], where c(S, [bar S]) is the sum of the costs of the edges crossing the cut and w(S) and w([bar S]) are the sum of the weights of the vertices in S and [bar S], respectively. The problem of finding a cut whose quotient is minimummore » for a graph has in recent years attracted considerable attention, due in large part to the work of Rao and Leighton and Rao. They have shown that an algorithm (exact or approximation) for the minimum-quotient-cut problem can be used to obtain an approximation algorithm for the more famous minimumb-balanced-cut problem, which requires finding a cut (S,[bar S]) minimizing c(S,[bar S]) subject to the constraint bW [le] w(S) [le] (1 [minus] b)W, where W is the total vertex weight and b is some fixed balance in the range 0 < b [le] [1/2]. Unfortunately, the minimum-quotient-cut problem is strongly NP-hard for general graphs, and the best polynomial-time approximation algorithm known for the general problem guarantees only a cut whose quotient is at mostO(lg n) times optimal, where n is the size of the graph. However, for planar graphs, the minimum-quotient-cut problem appears more tractable, as Rao has developed several efficient approximation algorithms for the planar version of the problem capable of finding a cut whose quotient is at most some constant times optimal. In this paper, we improve Rao's algorithms, both in terms of accuracy and speed. As our first result, we present two pseudopolynomial-time exact algorithms for the planar minimum-quotient-cut problem. As Rao's most accurate approximation algorithm for the problem -- also a pseudopolynomial-time algorithm -- guarantees only a 1.5-times-optimal cut, our algorithms represent a significant advance.« less

An investigation of the use of discriminant analysis for the classification of blade edge type from cut marks made by metal and bamboo blades.

PubMed

Bonney, Heather

2014-08-01

Analysis of cut marks in bone is largely limited to two dimensional qualitative description. Development of morphological classification methods using measurements from cut mark cross sections could have multiple uses across palaeoanthropological and archaeological disciplines, where cutting edge types are used to investigate and reconstruct behavioral patterns. An experimental study was undertaken, using porcine bone, to determine the usefulness of discriminant function analysis in classifying cut marks by blade edge type, from a number of measurements taken from their cross-sectional profile. The discriminant analysis correctly classified 86.7% of the experimental cut marks into serrated, non-serrated and bamboo blade types. The technique was then used to investigate a series of cut marks of unknown origin from a collection of trophy skulls from the Torres Strait Islands, to investigate whether they were made by bamboo or metal blades. Nineteen out of twenty of the cut marks investigated were classified as bamboo which supports the non-contemporaneous ethnographic accounts of the knives used for trophy taking and defleshing remains. With further investigation across a variety of blade types, this technique could prove a valuable tool in the interpretation of cut mark evidence from a wide variety of contexts, particularly in forensic anthropology where the requirement for presentation of evidence in a statistical format is becoming increasingly important. © 2014 Wiley Periodicals, Inc.

Computing the Edge-Neighbour-Scattering Number of Graphs

NASA Astrophysics Data System (ADS)

Wei, Zongtian; Qi, Nannan; Yue, Xiaokui

2013-11-01

A set of edges X is subverted from a graph G by removing the closed neighbourhood N[X] from G. We denote the survival subgraph by G=X. An edge-subversion strategy X is called an edge-cut strategy of G if G=X is disconnected, a single vertex, or empty. The edge-neighbour-scattering number of a graph G is defined as ENS(G) = max{ω(G/X)-|X| : X is an edge-cut strategy of G}, where w(G=X) is the number of components of G=X. This parameter can be used to measure the vulnerability of networks when some edges are failed, especially spy networks and virus-infected networks. In this paper, we prove that the problem of computing the edge-neighbour-scattering number of a graph is NP-complete and give some upper and lower bounds for this parameter.

The Cutting Edge: Workplace English. Instructional Guide.

ERIC Educational Resources Information Center

El Paso Community Coll., TX. Literacy Center.

The instructional guide for the Cutting Edge workplace literacy program, a cooperative project of El Paso Community College (Texas) and Levi Strauss and Company, is an expanded version of one appendix the project handbook. It describes and provides an instructional model for the three-part, job-specific, video-based program of English as a Second…

Cutting-Edge Technologies and Social Media Use in Higher Education

ERIC Educational Resources Information Center

Benson, Vladlena, Ed.; Morgan, Stephanie

2014-01-01

The inclusion of social media in higher education has transformed the way instructors teach and students learn. In order to effectively reach their students in this networked world, teachers must learn to utilize the latest technologies in their classrooms. "Cutting-Edge Technologies and Social Media Use in Higher Education" brings…

The Community College Baccalaureate Movement: Cutting-Edge Dissertation Research

ERIC Educational Resources Information Center

Hrabak, Michael R.

2009-01-01

In this review of dissertations, the researcher presents summaries of 10 of the most recent and cutting-edge dissertations focusing on the ever-growing and complex field of the community college baccalaureate movement. These studies focus on the gamut of specific legislation, case studies of particular programs and schools, financing of such…

Tapping Recent Alumni for the Development of Cutting-Edge, Investigative Teaching Laboratory Experiments

ERIC Educational Resources Information Center

Brodl, Mark R.

2005-01-01

This project presents a model for the development of an innovative, highly-experimental teaching laboratory course that centers upon collaborative efforts between recent alumni currently enrolled in Ph. D. programs (consultants) and current faculty. Because these consultants are involved in cutting-edge research, their combined talents represent a…

Virtual Workshop Experiences for Faculty: Lessons Learned from On the Cutting Edge

NASA Astrophysics Data System (ADS)

McDaris, J. R.; Kirk, K. B.; Mogk, D. W.; Bruckner, M. Z.

2010-12-01

The On the Cutting Edge professional development program for geoscience faculty has begun offering online workshops as a supplement to its face-to-face workshop series. Following a few initial forays since 2005, Cutting Edge launched a suite of four virtual workshops in 2010: Teaching Geoscience with Service Learning, Understanding the Deep Earth, Designing Effective and Innovative Courses in the Geosciences, and Teaching Geoscience Online. Each workshop was presented over 1-2 weeks and included pre-workshop web postings, synchronous whole-group presentations, live small-group discussions, asynchronous input via threaded discussions or editable web pages, and personal time for reflection and writing. Synchronous sessions were facilitated through the Elluminate software platform which includes tools for viewing presentations, screen sharing, real-time participant response, and an ongoing chat-room discussion. Audio was provided through a separate telephone conference service. In addition, many asynchronous conversations on workshop topics were held via a threaded discussion board on the Cutting Edge website and in Wiki-like, editable web pages designed to support collaborative work. A number of challenges to running online workshops exist, primarily involving participants’ time management. It is difficult for participants to set aside enough time to complete workshop activities when they are still enmeshed in their everyday lives. It also requires new skills for speakers, participants and support staff to prepare web-based materials and navigate the technology required for the online presentations. But there are also a number of opportunities presented by these experiences. With no travel needed, an online workshop is less expensive for participants, which allows Cutting Edge to extend its commitment to providing workshop materials to a wider audience of interested faculty. Also, synchronous sessions can be recorded and posted on the website for broader community access. In terms of best practices, the most important lesson learned is the need to make the experience as “real” as possible so that participants stay engaged and feel connected to the workshop experience. This can be accomplished by making the presentations interactive, continued leader participation in threaded discussions and break out groups, and providing multiple channels for contribution and participation. Despite some initial hesitation in jumping into a virtual environment, participants gained experience and became more comfortable with collaboration via online technologies. Participants had access to their own scientific and instructional materials at their home offices, and as a result could design and complete new teaching resources more effectively during the workshop. Peer review of new instructional resources was also completed during the workshop, and virtual networks were established to support continuing work. Online workshops can be used to effectively minimize costs, extend participation, build and sustain community networks, and develop thematic collections of instructional resources and activities. Based on the success of the 2010 workshops, more online workshops are planned for the coming years.

Phonon cross-plane transport and thermal boundary resistance: effect of heat source size and thermal boundary resistance on phonon characteristics

NASA Astrophysics Data System (ADS)

Ali, H.; Yilbas, B. S.

2016-09-01

Phonon cross-plane transport across silicon and diamond thin films pair is considered, and thermal boundary resistance across the films pair interface is examined incorporating the cut-off mismatch and diffusive mismatch models. In the cut-off mismatch model, phonon frequency mismatch for each acoustic branch is incorporated across the interface of the silicon and diamond films pair in line with the dispersion relations of both films. The frequency-dependent and transient solution of the Boltzmann transport equation is presented, and the equilibrium phonon intensity ratios at the silicon and diamond film edges are predicted across the interface for each phonon acoustic branch. Temperature disturbance across the edges of the films pair is incorporated to assess the phonon transport characteristics due to cut-off and diffusive mismatch models across the interface. The effect of heat source size, which is allocated at high-temperature (301 K) edge of the silicon film, on the phonon transport characteristics at the films pair interface is also investigated. It is found that cut-off mismatch model predicts higher values of the thermal boundary resistance across the films pair interface as compared to that of the diffusive mismatch model. The ratio of equilibrium phonon intensity due to the cut-off mismatch over the diffusive mismatch models remains >1 at the silicon edge, while it becomes <1 at the diamond edge for all acoustic branches.

The Seasonal Dynamics of Artificial Nest Predation Rates along Edges in a Mosaic Managed Reedbed

PubMed Central

Malzer, Iain; Helm, Barbara

2015-01-01

Boundaries between different habitats can be responsible for changes in species interactions, including modified rates of encounter between predators and prey. Such ‘edge effects’ have been reported in nesting birds, where nest predation rates can be increased at habitat edges. The literature concerning edge effects on nest predation rates reveals a wide variation in results, even within single habitats, suggesting edge effects are not fixed, but dynamic throughout space and time. This study demonstrates the importance of considering dynamic mechanisms underlying edge effects and their relevance when undertaking habitat management. In reedbed habitats, management in the form of mosaic winter reed cutting can create extensive edges which change rapidly with reed regrowth during spring. We investigate the seasonal dynamics of reedbed edges using an artificial nest experiment based on the breeding biology of a reedbed specialist. We first demonstrate that nest predation decreases with increasing distance from the edge of cut reed blocks, suggesting edge effects have a pivotal role in this system. Using repeats throughout the breeding season we then confirm that nest predation rates are temporally dynamic and decline with the regrowth of reed. However, effects of edges on nest predation were consistent throughout the season. These results are of practical importance when considering appropriate habitat management, suggesting that reed cutting may heighten nest predation, especially before new growth matures. They also contribute directly to an overall understanding of the dynamic processes underlying edge effects and their potential role as drivers of time-dependent habitat use. PMID:26448338

The effect of microstructure on the sheared edge quality and hole expansion ratio of hot-rolled 700 MPa steel

NASA Astrophysics Data System (ADS)

Kaijalainen, A.; Kesti, V.; Vierelä, R.; Ylitolva, M.; Porter, D.; Kömi, J.

2017-09-01

The effects of microstructure on the cutting and hole expansion properties of three thermomechanically rolled steels have been investigated. The yield strength of the studied 3 mm thick strip steels was approximately 700 MPa. Detailed microstructural studies using laser scanning confocal microscopy (LCSM), FESEM and FESEM-EBSD revealed that the three investigated materials consist of 1) single-phase polygonal ferrite, 2) polygonal ferrite with precipitates and 3) granular bainite. The quality of mechanically sheared edges were evaluated using visual inspection and LSCM, while hole expansion properties were characterised according to the methods described in ISO 16630. Roughness values (Ra and Rz) of the sheet edge with different cutting clearances varied between 12 µm to 21 µm and 133 µm to 225 µm, respectively. Mean hole expansion ratios varied from 28.4% to 40.5%. It was shown that granular bainite produced the finest cutting edge, but the hole expansion ratio remained at the same level as in the steel comprising single-phase ferrite. This indicates that a single-phase ferritic matrix enhances hole expansion properties even with low quality edges. A brief discussion of the microstructural features controlling the cutting quality and hole expansion properties is given.

Identifying Major Transitions in the Evolution of Lithic Cutting Edge Production Rates

PubMed Central

Clarkson, Chris

2016-01-01

The notion that the evolution of core reduction strategies involved increasing efficiency in cutting edge production is prevalent in narratives of hominin technological evolution. Yet a number of studies comparing two different knapping technologies have found no significant differences in edge production. Using digital analysis methods we present an investigation of raw material efficiency in eight core technologies broadly representative of the long-term evolution of lithic technology. These are bipolar, multiplatform, discoidal, biface, Levallois, prismatic blade, punch blade and pressure blade production. Raw material efficiency is assessed by the ratio of cutting edge length to original core mass. We also examine which flake attributes contribute to maximising raw material efficiency, as well as compare the difference between expert and intermediate knappers in terms of cutting edge produced per gram of core. We identify a gradual increase in raw material efficiency over the broad sweep of lithic technological evolution. The results indicate that the most significant transition in efficiency likely took place with the introduction of small foliate biface, Levallois and prismatic blade knapping, all introduced in the Middle Stone Age / Middle Palaeolithic among early Homo sapiens and Neanderthals. This suggests that no difference in raw material efficiency existed between these species. With prismatic blade technology securely dated to the Middle Palaeolithic, by including the more recent punch and pressure blade technology our results dispel the notion that the transition to the Upper Palaeolithic was accompanied by an increase in efficiency. However, further increases in cutting edge efficiency are evident, with pressure blades possessing the highest efficiency in this study, indicating that late/epi-Palaeolithic and Neolithic blade technologies further increased efficiency. PMID:27936135

Identifying Major Transitions in the Evolution of Lithic Cutting Edge Production Rates.

PubMed

Muller, Antoine; Clarkson, Chris

2016-01-01

The notion that the evolution of core reduction strategies involved increasing efficiency in cutting edge production is prevalent in narratives of hominin technological evolution. Yet a number of studies comparing two different knapping technologies have found no significant differences in edge production. Using digital analysis methods we present an investigation of raw material efficiency in eight core technologies broadly representative of the long-term evolution of lithic technology. These are bipolar, multiplatform, discoidal, biface, Levallois, prismatic blade, punch blade and pressure blade production. Raw material efficiency is assessed by the ratio of cutting edge length to original core mass. We also examine which flake attributes contribute to maximising raw material efficiency, as well as compare the difference between expert and intermediate knappers in terms of cutting edge produced per gram of core. We identify a gradual increase in raw material efficiency over the broad sweep of lithic technological evolution. The results indicate that the most significant transition in efficiency likely took place with the introduction of small foliate biface, Levallois and prismatic blade knapping, all introduced in the Middle Stone Age / Middle Palaeolithic among early Homo sapiens and Neanderthals. This suggests that no difference in raw material efficiency existed between these species. With prismatic blade technology securely dated to the Middle Palaeolithic, by including the more recent punch and pressure blade technology our results dispel the notion that the transition to the Upper Palaeolithic was accompanied by an increase in efficiency. However, further increases in cutting edge efficiency are evident, with pressure blades possessing the highest efficiency in this study, indicating that late/epi-Palaeolithic and Neolithic blade technologies further increased efficiency.

A cutting-edge solution for 1µm laser metal processing

NASA Astrophysics Data System (ADS)

Baumbach, N.; Kühl, P.; Karam, J.; Jonkers, J.; Villarreal-Saucedo, F.; Reyes, M.

2017-02-01

The recent 1μm-laser cutting market is dominated by fiber and disk lasers due to their excellent beam quality of below 4mm*mrad. Teradiode's 4kW direct diode laser source achieves similar beam quality while having a different beam shape and shorter wavelengths which are known for higher absorption rates at the inclined front of the cutting keyhole. Research projects, such as the HALO Project, have additionally shown that polarized radiation and beams with shapes different from the typical LG00 lead to improved cut quality for ferrous and non-ferrous metals. [1] Diode laser have the inherent property of not being sensitive to back reflection which brings advantages in cutting high-reflective materials. The II-VI HIGHYAG laser cutting head BIMO-FSC offers the unique feature of machine controlled and continuous adjustment of both the focus diameter and the focus position. This feature is proven to be beneficial for cutting and piercing with high speed and small hole diameters. In addition, the optics are designed for lowest focus shift. As a leading laser processing head manufacturer, II-VI HIGHYAG qualified its BIMO-FSC MZ (M=magnification, Z=focus position) cutting head for Teradiode's 4kW direct diode laser source to offer a cutting-edge solution for highpower laser cutting. Combining the magnification ability of the cutting head with this laser source, customers experience strong advantages in cutting metals in broad thickness ranges. Thicknesses up to 25mm mild steel can easily be cut with excellent edge quality. Furthermore, a new optical setup equivalent to an axicon with a variable axicon angle is demonstrated which generates variable sized ring spots. The setup provides new degrees of freedom to tailor the energy distribution for even higher productivity and quality.

Thin EFG octagons

NASA Astrophysics Data System (ADS)

Kalejs, J. P.

1994-03-01

This report describes work to advance the manufacturing line capabilities in crystal growth and laser cutting of Mobil Solar's unique edge-defined film-fed growth (EFG) octagon technology and to reduce the manufacturing costs of 10 cm x 10 cm polycrystalline silicon EFG wafers. The report summarizes the significant technical improvements in EFG technology achieved in the first 6 months of the PVMaT Phase 2 and the success in meeting program milestones. Technical results are reported for each of the three main pregrain areas: Task 5 -- Thin octagon growth (crystal growth) to reduce the thickness of the octagon to 200 microns; Task 6 -- Laser cutting-to improve the laser cutting process so as to produce wafers with decreased laser cutting damage at increased wafer throughput rates; and Task 7 -- Process control and product specification to implement advanced strategies in crystal growth process control and productivity designed to increase wafer yields.

Simulation of dynamic processes when machining transition surfaces of stepped shafts

NASA Astrophysics Data System (ADS)

Maksarov, V. V.; Krasnyy, V. A.; Viushin, R. V.

2018-03-01

The paper addresses the characteristics of stepped surfaces of parts categorized as "solids of revolution". It is noted that in the conditions of transition modes during the switch to end surface machining, there is cutting with varied load intensity in the section of the cut layer, which leads to change in cutting force, onset of vibrations, an increase in surface layer roughness, a decrease of size precision, and increased wear of a tool's cutting edge. This work proposes a method that consists in developing a CNC program output code that allows one to process complex forms of stepped shafts with only one machine setup. The authors developed and justified a mathematical model of a technological system for mechanical processing with consideration for the resolution of tool movement at the stages of transition processes to assess the dynamical stability of a system in the process of manufacturing stepped surfaces of parts of “solid of revolution” type.

50 CFR Figures 18a, 18b and 18c to... - Large Frame TED Escape Opening; Minimum Dimensions Using All-Bar Cuts (Triangular Cuts); Large...

Code of Federal Regulations, 2013 CFR

2013-10-01

... Dimensions Using All-Bar Cuts (Triangular Cuts); Large Frame TED Escape Opening; Minimum Dimensions Using All-Bar Cuts and Leading Edge Cut; Large Frame TED Escape Opening; Minimum Dimensions Using All-Points...—Large Frame TED Escape Opening; Minimum Dimensions Using All-Bar Cuts (Triangular Cuts); Large Frame TED...

50 CFR Figures 18a, 18b and 18c to... - Large Frame TED Escape Opening; Minimum Dimensions Using All-Bar Cuts (Triangular Cuts); Large...

Code of Federal Regulations, 2012 CFR

2012-10-01

... Dimensions Using All-Bar Cuts (Triangular Cuts); Large Frame TED Escape Opening; Minimum Dimensions Using All-Bar Cuts and Leading Edge Cut; Large Frame TED Escape Opening; Minimum Dimensions Using All-Points...—Large Frame TED Escape Opening; Minimum Dimensions Using All-Bar Cuts (Triangular Cuts); Large Frame TED...

50 CFR Figures 18a, 18b and 18c to... - Large Frame TED Escape Opening; Minimum Dimensions Using All-Bar Cuts (Triangular Cuts); Large...

Code of Federal Regulations, 2014 CFR

2014-10-01

... Dimensions Using All-Bar Cuts (Triangular Cuts); Large Frame TED Escape Opening; Minimum Dimensions Using All-Bar Cuts and Leading Edge Cut; Large Frame TED Escape Opening; Minimum Dimensions Using All-Points...—Large Frame TED Escape Opening; Minimum Dimensions Using All-Bar Cuts (Triangular Cuts); Large Frame TED...

U.S. Global Change Research Program National Climate Assessment Global Change Information System

NASA Technical Reports Server (NTRS)

Tilmes, Curt

2012-01-01

The program: a) Coordinates Federal research to better understand and prepare the nation for global change. b) Priori4zes and supports cutting edge scientific work in global change. c) Assesses the state of scientific knowledge and the Nation s readiness to respond to global change. d) Communicates research findings to inform, educate, and engage the global community.

Practical Partnerships--Standing on the Shoulders of Scientists

ERIC Educational Resources Information Center

Thorley, Charlotte

2009-01-01

"If I have seen further, it is because I have stood upon the shoulders of giants." Whenever the author hears this quote from Isaac Newton, she thinks about the work being done by the Royal Society in schools throughout the country, bringing science to life for their students. Much of it is also cutting edge, and represents the best of…

Quantum Max-flow/Min-cut

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui, Shawn X., E-mail: xingshan@math.ucsb.edu; Quantum Architectures and Computation Group, Microsoft Research, Redmond, Washington 98052; Freedman, Michael H., E-mail: michaelf@microsoft.com

2016-06-15

The classical max-flow min-cut theorem describes transport through certain idealized classical networks. We consider the quantum analog for tensor networks. By associating an integral capacity to each edge and a tensor to each vertex in a flow network, we can also interpret it as a tensor network and, more specifically, as a linear map from the input space to the output space. The quantum max-flow is defined to be the maximal rank of this linear map over all choices of tensors. The quantum min-cut is defined to be the minimum product of the capacities of edges over all cuts ofmore » the tensor network. We show that unlike the classical case, the quantum max-flow=min-cut conjecture is not true in general. Under certain conditions, e.g., when the capacity on each edge is some power of a fixed integer, the quantum max-flow is proved to equal the quantum min-cut. However, concrete examples are also provided where the equality does not hold. We also found connections of quantum max-flow/min-cut with entropy of entanglement and the quantum satisfiability problem. We speculate that the phenomena revealed may be of interest both in spin systems in condensed matter and in quantum gravity.« less

What's Your Story?: Dutch Library DOK's New Cutting-Edge Community Tech Projects

ERIC Educational Resources Information Center

Boekesteijn, Erik

2010-01-01

DOK, the cutting-edge library center in Delft, the Netherlands, has been finding new ways to elaborate on the social networking impulse. A good library unites people from all levels of society, and DOK's unique innovation department focuses specifically on how media can bring people together. It's doing so using technology to inspire and connect…

Information Commons Features Cutting-Edge Conservation and Technology

ERIC Educational Resources Information Center

Gilroy, Marilyn

2011-01-01

This article features Richard J. Klarchek Information Commons (IC) at Loyola University Chicago, an all-glass library building on the shore of Chicago's Lake Michigan that is not only a state-of-the-art digital research library and study space--it also runs on cutting-edge energy technology. The building has attracted attention and visitors from…

Design and Fabrication of Automatic Glass Cutting Machine

NASA Astrophysics Data System (ADS)

Veena, T. R.; Kadadevaramath, R. S.; Nagaraj, P. M.; Madhusudhan, S. V.

2016-09-01

This paper deals with the design and fabrication of the automatic glass or mirror cutting machine. In order to increase the accuracy of cut and production rate; and decrease the production time and accidents caused due to manual cutting of mirror or glass, this project aims at development of an automatic machine which uses a programmable logic controller (PLC) for controlling the movement of the conveyer and also to control the pneumatic circuit. In this machine, the work of the operator is to load and unload the mirror. The cutter used in this machine is carbide wheel with its cutting edge ground to a V-shaped profile. The PLC controls the pneumatic cylinder and intern actuates the cutter along the glass, a fracture layer is formed causing a mark to be formed below the fracture layer and a crack to be formed below the rib mark. The machine elements are designed using CATIA V5R20 and pneumatic circuit are designed using FESTO FLUID SIM software.

Gradient cuts and extremal edges in relative depth and figure-ground perception.

PubMed

Ghose, Tandra; Palmer, Stephen E

2016-02-01

Extremal edges (EEs) are borders consisting of luminance gradients along the projected edge of a partly self-occluding curved surface (e.g., a cylinder), with equiluminant contours (ELCs) that run approximately parallel to that edge. Gradient cuts (GCs) are similar luminance gradients with ELCs that intersect (are "cut" by) an edge that could be due to occlusion. EEs are strongly biased toward being seen as closer/figural surfaces (Palmer & Ghose, Psychological Science, 19(1), 77-83, 2008). Do GCs produce a complementary bias toward being seen as ground? Experiment 1 shows that, with EEs on the opposite side, GCs produce a ground bias that increases with increasing ELC angles between ELCs and the shared edge. Experiment 2 shows that, with flat surfaces on the opposite side, GCs do not produce a ground bias, suggesting that more than one factor may be operating. We suggest that two partially dissociable factors may operate for curved surfaces-ELC angle and 3-D surface convexity-that reinforce each other in the figural cues of EEs but compete with each other in GCs. Moreover, this figural bias is modulated by the presence of EEs and GCs, as specified by the ELC angle between ELCs and the shared contour.

[A case of chrome asthma induced by exposure to the stone cutter dust].

PubMed

Onizuka, Reiko; Tanabe, Kimiko; Nakayama, Yoshihisa; Fukuchi, Tetsuroh; Nakata, Kazunori; Hiki, Toshinobu

2006-12-01

The case of a forty-six year old, male patient with asthma caused by exposure to dust containing chrome is presented. When the patient was nineteen years old, he started working as a stonemason in a factory. He cut and ground stone with a stone-cutter to make statues and tombstones. Three years after staring to work, contact dermatitis was observed on his arms and hands. Within six years of work, he suffered from chronic coughing. After eight years, he experienced bronchial asthma attacks with wheezing and dyspnea. He had been exposed to dust for eight years before developing asthma. The symptoms increased gradually. He fell into severe asthma attacks causing unconsciousness and dyspnea. Several common therapies were not effective. The characteristics of his clinical course and occupational history suggested that the asthma must be caused by exposure to dust containing metal generated in the factory. Skin Patch Tests (SPT) were performed for cobalt, copper, iron, chrome, tin, and manganese salt. The result of the SPT indicated a strong positive result for potassium dichromate and positive for chromium sulfate, but did not show any indications in the control or for other metallic salt. Fluorescent X-ray analysis detected that chrome was present in the powder dust under the stone-cutter machine. However, the fluorescent X-ray analysis did not detect chrome in the stone materials. It was suggested that chrome must be contained in the metal dust generated from the steel cutter used to cut off and grind the stone. The metal component in the used cutter edge and the unused cutter edge were analyzed with electro-probe microanalyzer (EPMA). The result revealed that chrome was contained in the used, dull cutter edge and not in the new sharp cutter edge. Thus, the patient had been exposed to the dust containing chrome generated from part of the stainless steel of cutter. He had sensitized to chrome and this had caused the occupational chrome-asthma.

INTERIOR VIEW SHOWING PROTOTYPE BEGUN APRIL 1988 METHOD OF CUTTING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

INTERIOR VIEW SHOWING PROTOTYPE BEGUN APRIL 1988 METHOD OF CUTTING GLASS, "PERFECT TIN? MACHINE." MANUFACTURED IN DALLAS, TEXAS AND USED FOR CUTTING GLASS WITH A FINISHED EDGE. - Chambers-McKee Window Glass Company, Cutting House, Clay Avenue Extension, Jeannette, Westmoreland County, PA

Marshall Space Flight Center Research and Technology Report 2015

NASA Technical Reports Server (NTRS)

Keys, A. S. (Compiler); Tinker, M. L. (Compiler); Sivak, A. D. (Compiler); Morris, H. C. (Compiler)

2015-01-01

The investments in technology development we made in 2015 not only support the Agency's current missions, but they will also enable new missions. Some of these projects will allow us to develop an in-space architecture for human space exploration; Marshall employees are developing and testing cutting-edge propulsion solutions that will propel humans in-space and land them on Mars. Others are working on technologies that could support a deep space habitat, which will be critical to enable humans to live and work in deep space and on other worlds. Still others are maturing technologies that will help new scientific instruments study the outer edge of the universe-instruments that will provide valuable information as we seek to explore the outer planets and search for life.

Astronaut Rhea Seddon works on flyswatter-like snagging device

NASA Technical Reports Server (NTRS)

1985-01-01

Astronaut Rhea Seddon begins works on flyswatter-like snagging device to be used as an extension to the remote manipulator system (RMS) arm on Discovery for an attempt to trip a lever on the troubled Syncom-IV satellite. She is seated on the floor of the aft flight deck with a pair of scissors in her mouth. She is using an exacto knife to cut the extension out of plastic. Her jacket is floating in the bottom right edge of the frame.

DARPA Agreement HR0011-06-1-0028 (Robert C. Byrd Institute for Advanced Flexible Manufacturing)

DTIC Science & Technology

2011-12-13

cutting edge design software, state-of-the-art computer labs, manufacturing staff expertise, training resources, as well as video-teleconference...started its own Design Works labs in an effort to provide manufacturers, entrepreneurs, students, machinists and engineers with access to a one-stop...shop and turn their ideas and talent into new products. From a concept drawn on a napkin or the back of an envelope to a 3D design to a working

Computation of the Distribution of the Fiber-Matrix Interface Cracks in the Edge Trimming of CFRP

NASA Astrophysics Data System (ADS)

Wang, Fu-ji; Zhang, Bo-yu; Ma, Jian-wei; Bi, Guang-jian; Hu, Hai-bo

2018-04-01

Edge trimming is commonly used to bring the CFRP components to right dimension and shape in aerospace industries. However, various forms of undesirable machining damage occur frequently which will significantly decrease the material performance of CFRP. The damage is difficult to predict and control due to the complicated changing laws, causing unsatisfactory machining quality of CFRP components. Since the most of damage has the same essence: the fiber-matrix interface cracks, this study aims to calculate the distribution of them in edge trimming of CFRP, thereby to obtain the effects of the machining parameters, which could be helpful to guide the optimal selection of the machining parameters in engineering. Through the orthogonal cutting experiments, the quantitative relation between the fiber-matrix interface crack depth and the fiber cutting angle, cutting depth as well as cutting speed is established. According to the analysis on material removal process on any location of the workpiece in edge trimming, the instantaneous cutting parameters are calculated, and the formation process of the fiber-matrix interface crack is revealed. Finally, the computational method for the fiber-matrix interface cracks in edge trimming of CFRP is proposed. Upon the computational results, it is found that the fiber orientations of CFRP workpieces is the most significant factor on the fiber-matrix interface cracks, which can not only change the depth of them from micrometers to millimeters, but control the distribution image of them. Other machining parameters, only influence the fiber-matrix interface cracks depth but have little effect on the distribution image.

Dynamic anthropogenic edge effects on the distribution and diversity of fungi in fragmented old-growth forests.

PubMed

Ruete, Alejandro; Snäll, Tord; Jönsson, Mari

2016-07-01

Diversity patterns and dynamics at forest edges are not well understood. We disentangle the relative importance of edge-effect variables on spatio-temporal patterns in species richness and occupancy of deadwood-dwelling fungi in fragmented old-growth forests. We related richness and log occupancy by 10 old-growth forest indicator fungi and by two common fungi to log conditions in natural and anthropogenic edge habitats of 31 old-growth Picea abies forest stands in central Sweden. We compared edge-to-interior gradients (100 m) to the forest interior (beyond 100 m), and we analyzed stand-level changes after 10 yr. Both richness and occupancy of logs by indicator species was negatively related to adjacent young clear-cut edges, but this effect decreased with increasing clear-cut age. The occupancy of logs by indicator species also increased with increasing distance to the natural edges. In contrast, the occupancy of logs by common species was positively related or unrelated to distance to clear-cut edges regardless of the edge age, and this was partly explained by fungal specificity to substrate quality. Stand-level mean richness and mean occupancy of logs did not change for indicator or common species over a decade. By illustrating the importance of spatial and temporal dimensions of edge effects, we extend the general understanding of the distribution and diversity of substrate-confined fungi in fragmented old-growth forests. Our results highlight the importance of longer forest rotation times adjacent to small protected areas and forest set-asides, where it may take more than 50 yr for indicator species richness levels to recover to occupancy levels observed in the forest interior. Also, non-simultaneous clear-cutting of surrounding productive forests in a way that reduces the edge effect over time (i.e., dynamic buffers) may increase the effective core area of small forest set-asides and improve their performance on protecting species of special concern for conservation. © 2016 by the Ecological Society of America.

Controlled Bending of a Thin Mirror to Regain Figure after Warping due to Edge-Cutting

NASA Astrophysics Data System (ADS)

Humphries, C. M.

1990-03-01

A thin circular Cer-Vit mirror, diameter 1.3 m, that had been polished flat was cut along 10 edges to form a 12-sided pseudo-elliptical plate. As a result of the edge-cutting, the mirror distorted and an experiment that investigated the effect of reverse stressing to counteract the distortion is described and analysed. The configuration adopted for stressing the mirror when installed as a driven coudé flat in the UK Infrared Telescope is also described. The reverse stressing results can be understood in terms of thin plate theory for pure bending and, in general, if the distortion is toroidal (including the case of a sphere) an orthogonal pair of bending moments can be chosen that will remove the undesired curvatures.

Method of control position of laser focus during surfacing teeth of cutters

NASA Astrophysics Data System (ADS)

Zvezdin, V. V.; Hisamutdinov, R. M.; Rakhimov, R. R.; Israfilov, I. H.; Akhtiamov, R. F.

2017-09-01

Providing the quality laser of surfacing the edges of teeth requires control not only the energy of the radiation parameters, but also the position of the focal spot. The control channel of position of laser focus during surfacing, which determines the parameters of quality of the deposited layer, was calculated in the work. The parameters of the active opto-electronic system for the subsystem adjust the focus position relative to the deposited layer with a laser illumination of the cutting edges the teeth cutters were calculated, the model of a control channel based on thermal phenomena occurring in the zone of surfacing was proposed.

Technique for the application of a streamer-type fish tag

USGS Publications Warehouse

Joeris, Leonard S.

1953-01-01

Principal features of the technique are: attachment of the plastic tag by means of a nylon-thread loop prepared in advance of field work; use of a curved surgical needle with cutting edge and a split eye for application of the tag. The procedures for splitting the needle's eye and for applying the tag are described and illustrated by a series of photographs.

Physician Extender (Sr. NP or PA) | Center for Cancer Research

Cancer.gov

Be part of our mission to solve the most important, challenging and neglected problems in modern cancer research and patient care.  The National Cancer Institute’s Center for Cancer Research (CCR) is a world-leading cancer research organization working toward scientific breakthroughs at medicine’s cutting edge. Our scientists can’t do it alone. It takes an extraordinary team

The Role of Sleep in Changing Our Minds: A Psychologist's Discussion of Papers on Memory Reactivation and Consolidation in Sleep

ERIC Educational Resources Information Center

Cartwright, Rosalind D.

2004-01-01

The group of papers on memory reactivation and consolidation during sleep included in this volume represents cutting edge work in both animals and humans. They support that the two types of sleep serve different necessary functions. The role of slow wave sleep (SWS) is reactivation of the hippocampal-neocortical circuits activated during a waking…

Acoustic Emission Measurements for Tool Wear Evaluation in Drilling

NASA Astrophysics Data System (ADS)

Gómez, Martín P.; Migliori, Julio; Ruzzante, José E.; D'Attellis, Carlos E.

2009-03-01

In this work, the tool condition in a drilling process of SAE 1040 steel samples was studied by means of acoustic emission. The studied drill bits were modified with artificial and real failures, such as different degrees of wear in the cutting edge and in the outer corner. Some correlation between mean power of the acoustic emission parameters and the drill bit wear condition was found.

Mitigating cutting-induced plasticity in the contour method, Part 2: Numerical analysis

DOE PAGES

Muránsky, O.; Hamelin, C. J.; Hosseinzadeh, F.; ...

2016-02-10

Cutting-induced plasticity can have a significant effect on the measurement accuracy of the contour method. The present study examines the benefit of a double-embedded cutting configuration that relies on self-restraint of the specimen, relative to conventional edge-crack cutting configurations. A series of finite element analyses are used to simulate the planar sectioning performed during double-embedded and conventional edge-crack contour cutting configurations. The results of numerical analyses are first compared to measured results to validate the cutting simulations. The simulations are then used to compare the efficacy of different cutting configurations by predicting the deviation of the residual stress profile frommore » an original (pre-cutting) reference stress field, and the extent of cutting-induced plasticity. Comparisons reveal that while the double-embedded cutting configuration produces the most accurate residual stress measurements, the highest levels of plastic flow are generated in this process. As a result, this cutting-induced plastic deformation is, however, largely confined to small ligaments formed as a consequence of the sample sectioning process, and as such it does not significantly affect the back-calculated residual stress field.« less

Mitigating cutting-induced plasticity in the contour method, Part 2: Numerical analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muránsky, O.; Hamelin, C. J.; Hosseinzadeh, F.

Cutting-induced plasticity can have a significant effect on the measurement accuracy of the contour method. The present study examines the benefit of a double-embedded cutting configuration that relies on self-restraint of the specimen, relative to conventional edge-crack cutting configurations. A series of finite element analyses are used to simulate the planar sectioning performed during double-embedded and conventional edge-crack contour cutting configurations. The results of numerical analyses are first compared to measured results to validate the cutting simulations. The simulations are then used to compare the efficacy of different cutting configurations by predicting the deviation of the residual stress profile frommore » an original (pre-cutting) reference stress field, and the extent of cutting-induced plasticity. Comparisons reveal that while the double-embedded cutting configuration produces the most accurate residual stress measurements, the highest levels of plastic flow are generated in this process. As a result, this cutting-induced plastic deformation is, however, largely confined to small ligaments formed as a consequence of the sample sectioning process, and as such it does not significantly affect the back-calculated residual stress field.« less

Pupillometry: Cutting Edge Biometrics for Early Intervention in Increased Intracranial Pressure.

PubMed

John, Jennilee St

2015-10-01

The pupillometer, a cutting-edge biometric device, is a valuable assessment tool that can aid in the early detection and prompt treatment of neurological abnormalities. Pupil assessment is a critical component of the neurological examination, and manual pupil assessment leaves much room for error. Automated pupillometry improves the quality and reliability of pupillary and neurological assessments, ultimately improving patient outcomes. Copyright 2015, SLACK Incorporated.

The Landsat Image Mosaic of Antarctica (LIMA): A Cutting-Edge Way for Students and Teachers to Learn about Antarctica

ERIC Educational Resources Information Center

Campbell, Brian; Bindschadler, Robert

2009-01-01

By studying Antarctica via satellite and through ground-truthing research, we can learn where the ice is melting and why. The Landsat Image Mosaic of Antarctica (LIMA), a new and cutting-edge way for scientists, researchers, educators, students, and the public to look at Antarctica, supports this research and allows for unprecedented views of our…

Cutting Zone Temperature Identification During Machining of Nickel Alloy Inconel 718

NASA Astrophysics Data System (ADS)

Czán, Andrej; Daniš, Igor; Holubják, Jozef; Zaušková, Lucia; Czánová, Tatiana; Mikloš, Matej; Martikáň, Pavol

2017-12-01

Quality of machined surface is affected by quality of cutting process. There are many parameters, which influence on the quality of the cutting process. The cutting temperature is one of most important parameters that influence the tool life and the quality of machined surfaces. Its identification and determination is key objective in specialized machining processes such as dry machining of hard-to-machine materials. It is well known that maximum temperature is obtained in the tool rake face at the vicinity of the cutting edge. A moderate level of cutting edge temperature and a low thermal shock reduce the tool wear phenomena, and a low temperature gradient in the machined sublayer reduces the risk of high tensile residual stresses. The thermocouple method was used to measure the temperature directly in the cutting zone. An original thermocouple was specially developed for measuring of temperature in the cutting zone, surface and subsurface layers of machined surface. This paper deals with identification of temperature and temperature gradient during dry peripheral milling of Inconel 718. The measurements were used to identification the temperature gradients and to reconstruct the thermal distribution in cutting zone with various cutting conditions.

Welding And Cutting A Nickel Alloy By Laser

NASA Technical Reports Server (NTRS)

Banas, C. M.

1990-01-01

Technique effective and energy-efficient. Report describes evaluation of laser welding and cutting of Inconel(R) 718. Notes that electron-beam welding processes developed for In-718, but difficult to use on large or complex structures. Cutting of In-718 by laser fast and produces only narrow kerf. Cut edge requires dressing, to endure fatigue.

Development of methods of producing large areas of silicon sheet by the slicing of silicon ingots using Inside Diameter (I.D.) saws

NASA Technical Reports Server (NTRS)

Aharonyan, P.

1980-01-01

Modifications to a 16 inch STC automated saw included: a programmable feed system; a crystal rotating system; and a STC dynatrack blade boring and control system. By controlling the plating operation and by grinding the cutting edge, 16 inch I.D. blades were produced with a cutting edge thickness of .22 mm. Crystal rotation mechanism was used to slice 100 mm diameter crystals with a 16 inch blade down to a thickness of .20 mm. Cutting rates with crystal rotation were generally slower than with standard plunge I.D. slicing techniques. Using programmed feeds and programmed rotation, maximum cutting rates were from 0.3 to 1.0 inches per minute.

Performance of Metal Cutting on Endmills Manufactured by Cooling-Air and Minimum Quantity Lubrication Grinding

NASA Astrophysics Data System (ADS)

Inoue, Shigeru; Aoyama, Tojiro

Grinding fluids have been commonly used during the grinding of tools for their cooling and lubricating effect since the hard, robust materials used for cutting tools are difficult to grind. Grinding fluids help prevent a drop in hardness due to burning of the cutting edge and keep chipping to an absolute minimum. However, there is a heightened awareness of the need to improve the work environment and protect the global environment. Thus, the present study is aimed at applying dry grinding, cooling-air grinding, cooling-air grinding with minimum quantity lubrication (MQL), and oil-based fluid grinding to manufacturing actual endmills (HSS-Co). Cutting tests were performed by a vertical machining center. The results indicated that the lowest surface inclination values and longest tool life were obtained by cooling-air grinding with MQL. Thus, cooling-air grinding with MQL has been demonstrated to be at least as effective as oil-based fluid grinding.

Paronychia

MedlinePlus

... toenails, and an emery board for smoothing the edges. Trim nails after bathing, when they are softer. Trim fingernails with a slightly rounded edge. Trim toenails straight across and do not cut ...

Fibre laser cutting stainless steel: Fluid dynamics and cut front morphology

NASA Astrophysics Data System (ADS)

Pocorni, Jetro; Powell, John; Deichsel, Eckard; Frostevarg, Jan; Kaplan, Alexander F. H.

2017-01-01

In this paper the morphology of the laser cut front generated by fibre lasers was investigated by observation of the 'frozen' cut front, additionally high speed imaging (HSI) was employed to study the fluid dynamics on the cut front while cutting. During laser cutting the morphology and flow properties of the melt film on the cut front affect cut quality parameters such as cut edge roughness and dross (residual melt attached to the bottom of the cut edge). HSI observation of melt flow down a laser cutting front using standard cutting parameters is experimentally problematic because the cut front is narrow and surrounded by the kerf walls. To compensate for this, artificial parameters are usually chosen to obtain wide cut fronts which are unrepresentative of the actual industrial process. This paper presents a new experimental cutting geometry which permits HSI of the laser cut front using standard, commercial parameters. These results suggest that the cut front produced when cutting medium section (10 mm thick) stainless steel with a fibre laser and a nitrogen assist gas is covered in humps which themselves are covered by a thin layer of liquid. HSI observation and theoretical analysis reveal that under these conditions the humps move down the cut front at an average speed of approximately 0.4 m/s while the covering liquid flows at an average speed of approximately 1.1 m/s, with an average melt depth at the bottom of the cut zone of approximately 0.17 mm.

Modified soldering iron speeds cutting of synthetic materials

NASA Technical Reports Server (NTRS)

Schafer, W. G., Jr.

1966-01-01

Modified soldering iron cuts large lots of synthetic materials economically without leaving frayed or jagged edges. The soldering iron is modified by machining an axial slot in its heating element tip and mounting a cutting disk in it. An alternate design has an axially threaded bore in the tip to permit the use of various shapes of cutting blades.

Cutting holes in fabric-faced panels

NASA Technical Reports Server (NTRS)

Peterson, S. A.

1981-01-01

Tool has 2 carbide inserts that bore clean holes through fibrous material with knifelike slicing action. Cutting edge of insert is curved, with plane inner surface at 30 degree angle to tool axis. Drill press or hand-held drill can be used to hold cutting tool.

Universal router concept

NASA Technical Reports Server (NTRS)

Pesch, W. A.

1970-01-01

Portable universal router can cut holes of large diameter and irregular shapes, machine recesses, and drill holes with certain edge-distance limitations. Rectangular and round holes may be cut without a template.

Cutting Edge Research in Homeopathy: HRI's second international research conference in Rome.

PubMed

Tournier, Alexander L; Roberts, E Rachel

2016-02-01

Rome, 3rd-5th June 2015, was the setting for the Homeopathy Research Institute's (HRI) second conference with the theme 'Cutting Edge Research in Homeopathy'. Attended by over 250 delegates from 39 countries, this event provided an intense two and a half day programme of presentations and a forum for the sharing of ideas and the creation of international scientific collaborations. With 35 oral presentations from leaders in the field, the scientific calibre of the programme was high and the content diverse. This report summarises the key themes underpinning the cutting edge data presented by the speakers, including six key-note presentations, covering advancements in both basic and clinical research. Given the clear commitment of the global homeopathic community to high quality research, the resounding success of both Barcelona 2013 and Rome 2015 HRI conferences, and the dedicated support of colleagues, the HRI moves confidently forward towards the next biennial conference. Copyright © 2015.

Descriptive Analysis of In Vitro Cutting of Swine Mitral Cusps: Comparison of High-Power Laser and Scalpel Blade Cutting Techniques.

PubMed

Pinto, Nathali Cordeiro; Pomerantzeff, Pablo Maria Alberto; Deana, Alessandro; Zezell, Denise; Benetti, Carolina; Aiello, Vera Demarchi; Lopes, Luciana Almeida; Jatene, Fabio Biscegli; Chavantes, M Cristina

2017-02-01

The most common injury to the heart valve with rheumatic involvement is mitral stenosis, which is the reason for a big number of cardiac operations in Brazil. Commissurotomy is the traditional technique that is still widely used for this condition, although late postoperative restenosis is concerning. This study's purpose was to compare the histological findings of porcine cusp mitral valves treated in vitro with commissurotomy with a scalpel blade to those treated with high-power laser (HPL) cutting, using appropriate staining techniques. Five mitral valves from healthy swine were randomly divided into two groups: Cusp group (G1), cut with a scalpel blade (n = 5), and Cusp group (G2), cut with a laser (n = 5). G2 cusps were treated using a diode laser (λ = 980 nm, power = 9.0 W, time = 12 sec, irradiance = 5625 W/cm 2 , and energy = 108 J). In G1, no histological change was observed in tissue. A hyaline basophilic aspect was focally observed in G2, along with a dark red color on the edges and areas of lower birefringence, when stained with hematoxylin-eosin, Masson's trichrome, and Sirius red. Further, the mean distances from the cutting edge in cusps submitted to laser application and stained with Masson's trichrome and Sirius red were 416.7 and 778.6 μm, respectively, never overcoming 1 mm in length. Thermal changes were unique in the group submitted to HPL and not observed in the cusp group cut with a scalpel blade. The mean distance of the cusps' collagen injury from the cutting edge was less than 1 mm with laser treatment. Additional studies are needed to establish the histological evolution of the laser cutting and to answer whether laser cutting may avoid valvular restenosis better than blade cutting.

Piezoelectric polymer gated OFET: Cutting-edge electro-mechanical transducer for organic MEMS-based sensors

PubMed Central

Thuau, Damien; Abbas, Mamatimin; Wantz, Guillaume; Hirsch, Lionel; Dufour, Isabelle; Ayela, Cédric

2016-01-01

The growth of micro electro-mechanical system (MEMS) based sensors on the electronic market is forecast to be invigorated soon by the development of a new branch of MEMS-based sensors made of organic materials. Organic MEMS have the potential to revolutionize sensor products due to their light weight, low-cost and mechanical flexibility. However, their sensitivity and stability in comparison to inorganic MEMS-based sensors have been the major concerns. In the present work, an organic MEMS sensor with a cutting-edge electro-mechanical transducer based on an active organic field effect transistor (OFET) has been demonstrated. Using poly(vinylidenefluoride/trifluoroethylene) (P(VDF-TrFE)) piezoelectric polymer as active gate dielectric in the transistor mounted on a polymeric micro-cantilever, unique electro-mechanical properties were observed. Such an advanced scheme enables highly efficient integrated electro-mechanical transduction for physical and chemical sensing applications. Record relative sensitivity over 600 in the low strain regime (<0.3%) was demonstrated, which represents a key-step for the development of highly sensitive all organic MEMS-based sensors. PMID:27924853

Piezoelectric polymer gated OFET: Cutting-edge electro-mechanical transducer for organic MEMS-based sensors.

PubMed

Thuau, Damien; Abbas, Mamatimin; Wantz, Guillaume; Hirsch, Lionel; Dufour, Isabelle; Ayela, Cédric

2016-12-07

The growth of micro electro-mechanical system (MEMS) based sensors on the electronic market is forecast to be invigorated soon by the development of a new branch of MEMS-based sensors made of organic materials. Organic MEMS have the potential to revolutionize sensor products due to their light weight, low-cost and mechanical flexibility. However, their sensitivity and stability in comparison to inorganic MEMS-based sensors have been the major concerns. In the present work, an organic MEMS sensor with a cutting-edge electro-mechanical transducer based on an active organic field effect transistor (OFET) has been demonstrated. Using poly(vinylidenefluoride/trifluoroethylene) (P(VDF-TrFE)) piezoelectric polymer as active gate dielectric in the transistor mounted on a polymeric micro-cantilever, unique electro-mechanical properties were observed. Such an advanced scheme enables highly efficient integrated electro-mechanical transduction for physical and chemical sensing applications. Record relative sensitivity over 600 in the low strain regime (<0.3%) was demonstrated, which represents a key-step for the development of highly sensitive all organic MEMS-based sensors.

Ductile-regime turning of germanium and silicon

NASA Technical Reports Server (NTRS)

Blake, Peter N.; Scattergood, Ronald O.

1989-01-01

Single-point diamond turning of silicon and germanium was investigated in order to clarify the role of cutting depth in coaxing a ductile chip formation in normally brittle substances. Experiments based on the rapid withdrawal of the tool from the workpiece have shown that microfracture damage is a function of the effective depth of cut (as opposed to the nominal cutting depth). In essence, damage created by the leading edge of the tool is removed several revolutions later by lower sections of the tool edge, where the effective cutting depth is less. It appears that a truly ductile cutting response can be achieved only when the effective cutting depth, or critical chip thickness, is less than about 20 nm. Factors such as tool rake angle are significant in that they will affect the actual value of the critical chip thickness for transition from brittle to ductile response. It is concluded that the critical chip thickness is an excellent parameter for measuring the effects of machining conditions on the ductility of the cut and for designing tool-workpiece geometry in both turning and grinding.

Estimation of tool wear during CNC milling using neural network-based sensor fusion

NASA Astrophysics Data System (ADS)

Ghosh, N.; Ravi, Y. B.; Patra, A.; Mukhopadhyay, S.; Paul, S.; Mohanty, A. R.; Chattopadhyay, A. B.

2007-01-01

Cutting tool wear degrades the product quality in manufacturing processes. Monitoring tool wear value online is therefore needed to prevent degradation in machining quality. Unfortunately there is no direct way of measuring the tool wear online. Therefore one has to adopt an indirect method wherein the tool wear is estimated from several sensors measuring related process variables. In this work, a neural network-based sensor fusion model has been developed for tool condition monitoring (TCM). Features extracted from a number of machining zone signals, namely cutting forces, spindle vibration, spindle current, and sound pressure level have been fused to estimate the average flank wear of the main cutting edge. Novel strategies such as, signal level segmentation for temporal registration, feature space filtering, outlier removal, and estimation space filtering have been proposed. The proposed approach has been validated by both laboratory and industrial implementations.

Cutter-loader apparatus having overhung shearer drum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Groger, H.; Harms, E.E.

1984-05-01

A longwall mining machine includes a drum cutter-loader and face conveyor wherein the drum cutter-loader is overhung and is supported by a support arm adjacent to the mine face. Nozzles direct high pressure liquid jets against the forward edge of the support arm to cut away the mining face and permit the face side support arm to advance as the mining machine advances. In one embodiment the nozzles are provided along an inclined cutting edge at the forward end of the support arm. Such nozzles may be fixed or oscillating. In an alternative embodiment the nozzles are provided in themore » cylindrical edge zone of the shearer drum and direct the high pressure fluid jets against the cutter edge at the forward end of the support arm.« less

Tubing cutter for tight spaces

NASA Technical Reports Server (NTRS)

Girala, A. S.

1980-01-01

Cutter requires few short swings of handle to rotate its cutting edge full 360 around tube. It will cut tubing installed in confined space that prevents free movement of conventional cutter. Cutter is snapped onto tube and held in place by spring-loaded clamp. Screw ratchet advances cutting wheel.

Strength of inserts in titanium alloy machining

NASA Astrophysics Data System (ADS)

Kozlov, V.; Huang, Z.; Zhang, J.

2016-04-01

In this paper, a stressed state of a non-worn cutting wedge in a machined titanium alloy (Ti6Al2Mo2Cr) is analyzed. The distribution of contact loads on the face of a cutting tool was obtained experimentally with the use of a ‘split cutting tool’. Calculation of internal stresses in the indexable insert made from cemented carbide (WC8Co) was carried out with the help of ANSYS 14.0 software. Investigations showed that a small thickness of the cutting insert leads to extremely high compressive stresses near the cutting edge, stresses that exceed the ultimate compressive strength of cemented carbide. The face and the base of the insert experience high tensile stresses, which approach the ultimate tensile strength of cemented carbide and increase a probability of cutting insert destruction. If the thickness of the cutting insert is bigger than 5 mm, compressive stresses near the cutting edge decrease, and tensile stresses on the face and base decrease to zero. The dependences of the greatest normal and tangential stresses on thickness of the cutting insert were found. Abbreviation and symbols: m/s - meter per second (cutting speed v); mm/r - millimeter per revolution (feed rate f); MPa - mega Pascal (dimension of specific contact loads and stresses); γ - rake angle of the cutting tool [°] α - clearance angle of the sharp cutting tool [°].

Experiments and FE-simulations of stretch flanging of DP-steels with different shear cut edge quality

NASA Astrophysics Data System (ADS)

Sigvant, M.; Falk, J.; Pilthammar, J.

2017-09-01

Dual-Phase (DP) steels are today used in the automotive industry due to its large strength to weight ratio. However, the high strength of DP-steel does have a negative impact on the general formability in sheet metal forming. Unfavourable process conditions in the press shop will, on top of this, reduce the formability of DP-steels even more. This paper addresses the problem of edge fracture in stretch flanges in sheet metal parts made of DP-steel. The experimental part involves tests of ten different DP590 and DP780 steel grades with three different shear cut qualities. The influence on the fracture strain of the sample orientation of the shear cut are also studied by facing the burr away or towards the punch and testing samples with the cut edge parallel with the rolling direction and the transverse direction. The strains are measured with an ARAMIS system in each test, together with punch displacement and punch force. All tests are then simulated with AutoFormplus R7 and the results from these simulations are compared with the experimental results in order to find the appropriate failure strain for each combination of supplier, coating, thickness and shear cut quality.

Finesse of transparent tissue cutting by ultrafast lasers at various wavelengths.

PubMed

Wang, Jenny; Schuele, Georg; Palanker, Daniel

2015-01-01

Transparent ocular tissues, such as the cornea and crystalline lens, can be ablated or dissected using short-pulse lasers. In refractive and cataract surgeries, the cornea, lens, and lens capsule can be cut by producing dielectric breakdown in the focus of a near-infrared (IR) femtosecond laser, which results in explosive vaporization of the interstitial water, causing mechanical rupture of the surrounding tissue. Here, we compare the texture of edges of lens capsule cut by femtosecond lasers with IR and ultraviolet (UV) wavelengths and explore differences in interactions of these lasers with biological molecules. Scanning electron microscopy indicates that a 400-nm laser is capable of producing very smooth cut edges compared to 800 or 1030 nm at a similar focusing angle. Using gel electrophoresis and liquid chromatography/mass spectrometry, we observe laser-induced nonlinear breakdown of proteins and polypeptides by 400-nm femtosecond pulses above and below the dielectric breakdown threshold. On the other hand, 800-nm femtosecond lasers do not produce significant dissociation even above the threshold of dielectric breakdown. However, despite this additional interaction of UV femtosecond laser with proteins, we determine that efficient cutting requires plasma-mediated bubble formation and that remarkably smooth edges are the result of reduced thresholds and smaller focal volume.

The effects of ion gun beam voltage on the electrical characteristics of NbCN/PbBi edge junctions

NASA Technical Reports Server (NTRS)

Lichtenberger, A. W.; Feldman, M. J.; Mattauch, R. J.; Cukauskas, E. J.

1989-01-01

The authors have succeeded in fabricating high-quality submicron NbCN edge junctions using a technique which is commonly used to make Nb edge junctions. A modified commercial ion gun was used to cut an edge in SiO2/NbCN films partially covered with photoresist. An insulating barrier was then formed on the exposed edge by reactive ion beam oxidation, and a counterelectrode of PbBi was deposited. The electrical quality of the resulting junctions was found to be strongly influenced by the ion beam acceleration voltages used to cut the edge and to oxidize it. For low ion beam voltages, the junction quality parameter was as high as Vm = 55 mV (measured at 3 mV), but higher ion beam voltages yielded strikingly poorer quality junctions. In light of the small coherence length of NbN, the dependence of the electrical characteristics on ion beam voltage is presumably due to mechanical damage of the NbCN surface. In contrast, for similar ion beam voltages, no such dependence was found for Nb edge junctions.

Little Caney River Prehistory. 1979 Field Season,

DTIC Science & Technology

1981-01-01

spurred tool used graver for puncturing soft materials, incising bone or skins 4o-t 22 Cutting tool A purposefully modified flake tool with working edge...of two facial implements do occur. The debitage burins(Figure4j-k)madeonthickflakeblanks. includes whole or fragmentary flakes having Incising of...is also sand tempered and-pecked. The ground stone slab/abrader is and is simple stamped or linearly incised on ground-and-marred and is from 50 cm

Assessing edge cracking resistance in AHSS automotive parts by the Essential Work of Fracture methodology

NASA Astrophysics Data System (ADS)

Frómeta, D.; Tedesco, M.; Calvo, J.; Lara, A.; Molas, S.; Casellas, D.

2017-09-01

Lightweight designs and demanding safety requirements in automotive industry are increasingly promoting the use of Advanced High Strength Steel (AHSS) sheets. Such steels present higher strength (above 800 MPa) but lower ductility than conventional steels. Their great properties allow the reduction of the thickness of automobile structural components without compromising the safety, but also introduce new challenges to parts manufacturers. The fabrication of most cold formed components starts from shear cut blanks and, due to the lower ductility of AHSS, edge cracking problems can appear during forming operations, forcing the stop of the production and slowing down the industrial process. Forming Limit Diagrams (FLD) and FEM simulations are very useful tools to predict fracture problems in zones with high localized strain, but they are not able to predict edge cracking. It has been observed that the fracture toughness, measured through the Essential Work of Fracture (EWF) methodology, is a good indicator of the stretch flangeability in AHSS and can help to foresee this type of fractures. In this work, a serial production automotive component has been studied. The component showed cracks in some flanged edges when using a dual phase steel. It is shown that the conventional approach to explain formability, based on tensile tests and FLD, fails in the prediction of edge cracking. A new approach, based on fracture mechanics, help to solve the problem by selecting steel grades with higher fracture toughness, measured by means of EWF. Results confirmed that fracture toughness, in terms of EWF, can be readily used as a material parameter to rationalize cracking related problems and select AHSS with improved edge cracking resistance.

Advances in the Study of the Middle Cranial Fossa through Cutting Edge Neuroimaging Techniques.

PubMed

Juanes Méndez, Juan A; Ruisoto, Pablo; Paniagua, Juan C; Prats, Alberto

2018-01-16

The objective of this paper is to present a morphometric study of the middle cranial fossa from the study of 87 patients using cutting edge multislice computed tomography scans (32 detectors) and Magnetic Resonance Imaging. The study presents a detailed anatomical-radiological and morphometric analysis of the middle cranial fossa as well as its neurovascular elements in normal conditions. The implications of this investigation in training and clinical contexts are discussed.

Enameloid microstructure of the serrated cutting edges in certain fossil carcharhiniform and lamniform sharks.

PubMed

Andreev, Plamen S

2010-07-01

The triple-layered enameloid organization of neoselachian teeth has proven to be a reliable systematic character of the group. This study uses scanning electron microscopy to investigate the orientation of the parallel enameloid bundles in the area of the serrated cutting edges in certain fossil elasmobranchs. The examined teeth come from two Upper Cretaceous Squalicorax species and the Upper Miocene carcharhiniforms Galeocerdo sp., Carcharhinus sp., and Hemipristis serra. The parallel bundles are revealed by surface etching, which removes the superficial shiny-layered enameloid. In the teeth of Squalicorax, the bundles around the cutting edge bend once, before they reach the serrations. The studied carcharhiniform species show a more complicated pattern with a change of parallel bundle course inside the serrations. H. serra teeth do not display the first bending of the bundles, whereas it was present in the other two carcharhiniforms. The course of the crystalline bundles in both Squalicorax species is not affected by the presence of the serrations, regardless of the twofold difference in tooth size between them. In the carcharhiniform species, the bended bundles occur within the primary and secondary serrations and are always associated with them. This feature might have functional significance by strengthening the cutting edge or could simply develop as a consequence of the enameloid mineralization around the individual serrae. (c) 2009 Wiley-Liss, Inc.

Dermatology education and the Internet: traditional and cutting-edge resources.

PubMed

Hanson, Anne H; Krause, L Kendall; Simmons, Rachel N; Ellis, Jeffrey I; Gamble, Ryan G; Jensen, J Daniel; Noble, Melissa N; Orser, Michael L; Suarez, Andrea L; Dellavalle, Robert P

2011-10-01

The number and variety of dermatological medical resources available online has grown exponentially over the past decade. Internet-based resources allow for immediate and easy access to information for both medical education and reference purposes. Although clinicians continue to turn to the Internet for clinical information and still images, tech-savvy medical students are currently accessing a variety of exciting new resources, including discussion boards, wikis, streaming video, podcasts, journal clubs, online communities, and interactive diagnostic experiences to augment their medical education. The objective of this study was to identify traditional and cutting-edge online dermatology resources. We present a sampling of the top dermatology Internet resources, as assessed by a group of medical students in our university dermatology research lab. These resources were ranked by using a matrix derived from the Silberg Criteria, which assessed authorship, attribution, disclosure, currency, and content. Results indicate comparable ranking and approval of cutting-edge resources as traditional online sources. The ranked resources in each category are provided with URLs for readers' use. These cutting-edge online dermatology resources represent excellent sources for continuing education for students and clinicians alike. Resources such as these likely represent the future of medical education, as they allow for self-directed and supplementary education as well as remote access. Copyright © 2010 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

A model for managing edge effects in harvest scheduling using spatial optimization

Treesearch

Kai L. Ross; Sándor F. Tóth

2016-01-01

Actively managed forest stands can create new forest edges. If left unchecked over time and across space, forest operations such as clear-cuts can create complex networks of forest edges. Newly created edges alter the landscape and can affect many environmental factors. These altered environmental factors have a variety of impacts on forest growth and structure and can...

Removal of millimeter-scale rolled edges using bevel-cut-like tool influence function in magnetorheological jet polishing.

PubMed

Yang, Hao; Cheng, Haobo; Feng, Yunpeng; Jing, Xiaoli

2018-05-01

Subaperture polishing techniques usually produce rolled edges due to edge effect. The rolled edges, especially those in millimeter scale on small components, are difficult to eliminate using conventional polishing methods. Magnetorheological jet polishing (MJP) offers the possibility of the removal of these structures, owing to its small tool influence function (TIF) size. Hence, we investigate the removal characters of inclined MJP jetting models by means of computational fluid dynamics (CFD) simulations and polishing experiments. A discrete phase model (DPM) is introduced in the simulation to get the influence of abrasive particle concentration on the removal mechanism. Therefore, a more accurate model for MJP removal mechanisms is built. With several critical problems solved, a small bevel-cut-like TIF (B-TIF), which has fine acentric and unimodal characteristics, is obtained through inclined jetting. The B-TIF proves to have little edge effect and is applied in surface polishing of thin rolled edges. Finally, the RMS of the experimental section profile converges from 10.5 nm to 1.4 nm, and the rolled edges are successfully suppressed. Consequently, it is validated that the B-TIF has remarkable ability in the removal of millimeter-scale rolled edges.

Zero degree contour cutting below 100 μm feature size with femtosecond laser

NASA Astrophysics Data System (ADS)

Stolberg, Klaus; Friedel, Susanna

2016-03-01

By the use of a 16 W femtosecond laser we demonstrate steep wall angles and small feature spacings for non-thermal melt-free laser drilling and contour cutting of 100 to 500 μm thick metals like Cu-alloy, stainless steel, titanium and tantalum as well as for ceramics and polymer (polycarbonate). Especially processing of thin materials is a challenge, because heat accumulation in thermal processing usually causes mechanical distortion or edge melting as well as material. The combination of beam deflection in trepanning optics and sample motion allowed us to work in a special "laser milling mode" with rotating beam. Zero degree taper angle as well as positive or negative tapers can be achieved at micrometer scale.

Hard particle effect on surface generation in nano-cutting

NASA Astrophysics Data System (ADS)

Xu, Feifei; Fang, Fengzhou; Zhang, Xiaodong

2017-12-01

The influence of the hard particle on the surface generation, plastic deformation and processing forces in nano-cutting of aluminum is investigated by means of molecular dynamics simulations. In this investigation, a hard particle which is simplified as a diamond ball is embedded under the free surface of workpiece with different depths. The influence of the position of the hard ball on the surface generation and other material removal mechanism, such as the movement of the ball under the action of cutting tool edge, is revealed. The results show that when the hard particle is removed, only a small shallow pit is left on the machined surface. Otherwise, it is pressed down to the subsurface of the workpiece left larger and deeper pit on the generated surface. Besides that, the hard particle in the workpiece would increase the processing force when the cutting tool edge or the plastic carriers interact with the hard particle. It is helpful to optimize the cutting parameters and material properties for obtaining better surface quality in nano-cutting of composites or other materials with micro/nanoscale hard particles in it.

Flow visualization over a thick blunt trailing-edge airfoil with base cavity at low Reynolds numbers using PIV technique.

PubMed

Taherian, Gholamhossein; Nili-Ahmadabadi, Mahdi; Karimi, Mohammad Hassan; Tavakoli, Mohammad Reza

2017-01-01

In this study, the effect of cutting the end of a thick airfoil and adding a cavity on its flow pattern is studied experimentally using PIV technique. First, by cutting 30% chord length of the Riso airfoil, a thick blunt trialing-edge airfoil is generated. The velocity field around the original airfoil and the new airfoil is measured by PIV technique and compared with each other. Then, adding two parallel plates to the end of the new airfoil forms the desired cavity. Continuous measurement of unsteady flow velocity over the Riso airfoil with thick blunt trailing edge and base cavity is the most important innovation of this research. The results show that cutting off the end of the airfoil decreases the wake region behind the airfoil, when separation occurs. Moreover, adding a cavity to the end of the thickened airfoil causes an increase in momentum and a further decrease in the wake behind the trailing edge that leads to a drag reduction in comparison with the thickened airfoil without cavity. Furthermore, using cavity decreases the Strouhal number and vortex shedding frequency.

Process Damping and Cutting Tool Geometry in Machining

NASA Astrophysics Data System (ADS)

Taylor, C. M.; Sims, N. D.; Turner, S.

2011-12-01

Regenerative vibration, or chatter, limits the performance of machining processes. Consequences of chatter include tool wear and poor machined surface finish. Process damping by tool-workpiece contact can reduce chatter effects and improve productivity. Process damping occurs when the flank (also known as the relief face) of the cutting tool makes contact with waves on the workpiece surface, created by chatter motion. Tool edge features can act to increase the damping effect. This paper examines how a tool's edge condition combines with the relief angle to affect process damping. An analytical model of cutting with chatter leads to a two-section curve describing how process damped vibration amplitude changes with surface speed for radiussed tools. The tool edge dominates the process damping effect at the lowest surface speeds, with the flank dominating at higher speeds. A similar curve is then proposed regarding tools with worn edges. Experimental data supports the notion of the two-section curve. A rule of thumb is proposed which could be useful to machine operators, regarding tool wear and process damping. The question is addressed, should a tool of a given geometry, used for a given application, be considered as sharp, radiussed or worn regarding process damping.

Living in space, book 2, levels D, E, F

NASA Technical Reports Server (NTRS)

Andrews, Sheila Briskin; Kirschenbaum, Audrey

1987-01-01

In June 1984, President Reagan announced a new NASA program, Operation Liftoff. For more than 25 years NASA has pioneered on the cutting edge of science and technology and has stimulated our young people to strive for excellence in all they do. This program is designed to encourage pupils in the nation's elementary schools to take a greater interest in mathematics and science. Areas addressed include: food, clothing, health, housing, communication, and working in space.

Effect of Moisture Content of Paper Material on Laser Cutting

NASA Astrophysics Data System (ADS)

Stepanov, Alexander; Saukkonen, Esa; Piili, Heidi; Salminen, Antti

Laser technology has been used in industrial processes for several decades. The most advanced development and implementation took place in laser welding and cutting of metals in automotive and ship building industries. However, there is high potential to apply laser processing to other materials in various industrial fields. One of these potential fields could be paper industry to fulfill the demand for high quality, fast and reliable cutting technology. Difficulties in industrial application of laser cutting for paper industry are associated to lack of basic information, awareness of technology and its application possibilities. Nowadays possibilities of using laser cutting for paper materials are widened and high automation level of equipment has made this technology more interesting for manufacturing processes. Promising area of laser cutting application at paper making machines is longitudinal cutting of paper web (edge trimming). There are few locations at a paper making machine where edge trimming is usually done: wet press section, calender or rewinder. Paper web is characterized with different moisture content at different points of the paper making machine. The objective of this study was to investigate the effect of moisture content of paper material on laser cutting parameters. Effect of moisture content on cellulose fibers, laser absorption and energy needed for cutting is described as well. Laser cutting tests were carried out using CO2 laser.

Mitigation of EMU Cut Glove Hazard from Micrometeoroid and Orbital Debris Impacts on ISS Handrails

NASA Technical Reports Server (NTRS)

Ryan, Shannon; Christiansen, Eric L.; Davis, Bruce A.; Ordonez, Erick

2009-01-01

Recent cut damages sustained on crewmember gloves during extravehicular activity (ISS) onboard the International Space Station (ISS) have been caused by contact with sharp edges or a pinch point according to analysis of the damages. One potential source are protruding sharp edged crater lips from micrometeoroid and orbital debris (MMOD) impacts on metallic handrails along EVA translation paths. A number of hypervelocity impact tests were performed on ISS handrails, and found that mm-sized projectiles were capable of inducing crater lip heights two orders of magnitude above the minimum value for glove abrasion concerns. Two techniques were evaluated for mitigating the cut glove hazard of MMOD impacts on ISS handrails: flexible overwraps which act to limit contact between crewmember gloves and impact sites, and; alternate materials which form less hazardous impact crater profiles. In parallel with redesign efforts to increase the cut resilience of EMU gloves, the modifications to ISS handrails evaluated in this study provide the means to significantly reduce cut glove risk from MMOD impact craters

Nanosecond plasma-mediated electrosurgery with elongated electrodes

NASA Astrophysics Data System (ADS)

Vankov, Alexander; Palanker, Daniel

2007-06-01

Progress in interventional medicine is associated with the development of more delicate and less invasive surgical procedures, which requires more precise and less traumatic, yet affordable, surgical instruments. Previously we reported on the development of the pulsed electron avalanche knife for dissection of soft tissue in liquid media using the 100 ns plasma-mediated electric discharges applied via a 25 μm disk microelectrode. Cavitation bubbles accompanying explosive vaporization of the liquid medium in front of such a pointed electrode produced a series of craters that did not always merge into a continuous cut. In addition, this approach of surface ablation provided a limited depth of cutting. Application of an elongated electrode capable of cutting with its edge rather than just with its pointed apex faces a problem of nonuniformity of the electric field on a nonspherical electrode. In this article we explore dynamics of the plasma-mediated nanosecond discharges in liquid medium in positive and negative polarities and describe the geometry of an electrode that provides a sufficiently uniform electric field along an extended edge of a surgical probe. A highly enhanced and uniform electric field was obtained on very sharp (2.5 μm) exposed edges of a planar electrode insulated on its flat sides. Uniform ionization and simultaneous vaporization was obtained along the whole edge of such a blade with 100 ns pulses at 4-6 kV. A continuous cutting rate of 1 mm/s in the retina and in soft membranes was achieved at a pulse repetition rate of 100 Hz. The collateral damage zone at the edges of incision did not exceed 80 μm. Negative polarity was found advantageous due to the lower rate of electrode erosion and due to better spatial confinement of the plasma-mediated discharge in liquid.

Vision-based Nano Robotic System for High-throughput Non-embedded Cell Cutting

NASA Astrophysics Data System (ADS)

Shang, Wanfeng; Lu, Haojian; Wan, Wenfeng; Fukuda, Toshio; Shen, Yajing

2016-03-01

Cell cutting is a significant task in biology study, but the highly productive non-embedded cell cutting is still a big challenge for current techniques. This paper proposes a vision-based nano robotic system and then realizes automatic non-embedded cell cutting with this system. First, the nano robotic system is developed and integrated with a nanoknife inside an environmental scanning electron microscopy (ESEM). Then, the positions of the nanoknife and the single cell are recognized, and the distance between them is calculated dynamically based on image processing. To guarantee the positioning accuracy and the working efficiency, we propose a distance-regulated speed adapting strategy, in which the moving speed is adjusted intelligently based on the distance between the nanoknife and the target cell. The results indicate that the automatic non-embedded cutting is able to be achieved within 1-2 mins with low invasion benefiting from the high precise nanorobot system and the sharp edge of nanoknife. This research paves a way for the high-throughput cell cutting at cell’s natural condition, which is expected to make significant impact on the biology studies, especially for the in-situ analysis at cellular and subcellular scale, such as cell interaction investigation, neural signal transduction and low invasive cell surgery.

How cutting-edge technologies impact the design of electrochemical (bio)sensors for environmental analysis. A review.

PubMed

Arduini, Fabiana; Cinti, Stefano; Scognamiglio, Viviana; Moscone, Danila; Palleschi, Giuseppe

2017-03-22

Through the years, scientists have developed cutting-edge technologies to make (bio)sensors more convenient for environmental analytical purposes. Technological advancements in the fields of material science, rational design, microfluidics, and sensor printing, have radically shaped biosensor technology, which is even more evident in the continuous development of sensing systems for the monitoring of hazardous chemicals. These efforts will be crucial in solving some of the problems constraining biosensors to reach real environmental applications, such as continuous analyses in field by means of multi-analyte portable devices. This review (with 203 refs.) covers the progress between 2010 and 2015 in the field of technologies enabling biosensor applications in environmental analysis, including i) printing technology, ii) nanomaterial technology, iii) nanomotors, iv) biomimetic design, and (v) microfluidics. Next section describes futuristic cutting-edge technologies that are gaining momentum in recent years, which furnish highly innovative aspects to biosensing devices. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of the breakdown behaviour of ATLAS silicon pixel sensors after partial guard-ring removal

NASA Astrophysics Data System (ADS)

Goessling, C.; Klingenberg, R.; Muenstermann, D.; Wittig, T.

2010-12-01

To avoid geometrical inefficiencies in the ATLAS pixel detector, the concept of shingling is used up to now in the barrel section. For the upgrades of ATLAS, it is desired to avoid this as it increases the volume and material budget of the pixel layers and complicates the cooling. A direct planar edge-to-edge arrangement of pixel modules has not been possible in the past due to about 1100 μm of inactive edge composed of approximately 600 μm of guard rings and 500 μm of safety margin. In this work, the safety margin and guard rings of ATLAS SingleChip sensors were cut at different positions using a standard diamond dicing saw and irradiated afterwards to explore the breakdown behaviour and the leakage current development. It is found that the inactive edge can be reduced to about 400 μm of guard rings with almost no reduction in pre-irradiation testability and leakage current performance. This is in particular important for the insertable b-layer upgrade of ATLAS (IBL) where inactive edges of less than 450 μm width are required.

Cutting thin sections of bone

NASA Technical Reports Server (NTRS)

Ashley, W. W.

1972-01-01

Medical equipment for obtaining repetitive planoparallel sections of bone to study healing of bone structure under high gravity stress is described. Device consists of modified saw with diamond cutting edges. Construction of device and manner of use are explained.

Surgeon General Outlines Opioid Plan | NIH MedlinePlus the Magazine

MedlinePlus

... staff, Dr. Adams said the opioid epidemic is cutting too many American lives short. “Ninety-one Americans ... public health data and reporting Providing support for cutting-edge research on pain and addiction Advancing the ...

Research Results Of Stress-Strain State Of Cutting Tool When Aviation Materials Turning

NASA Astrophysics Data System (ADS)

Serebrennikova, A. G.; Nikolaeva, E. P.; Savilov, A. V.; Timofeev, S. A.; Pyatykh, A. S.

2018-01-01

Titanium alloys and stainless steels are hard-to-machine of all the machining types. Cutting edge state of turning tool after machining titanium and high-strength aluminium alloys and corrosion-resistant high-alloy steel has been studied. Cutting forces and chip contact arears with the rake surface of cutter has been measured. The relationship of cutting forces and residual stresses are shown. Cutting forces and residual stresses vs value of cutting tool rake angle relation were obtained. Measurements of residual stresses were performed by x-ray diffraction.

The effect of handpiece spray patterns on cutting efficiency.

PubMed

Siegel, Sharon C; von Fraunhofer, J Anthony

2002-02-01

High-speed handpieces' spray ports direct coolant at the cutting interface. The authors evaluated the effect of the number of ports and their positions on cutting rates, or CRs. The authors performed cutting studies on a machinable ceramic block using an established testing regimen. One-port, three-port and four-port handpieces from one manufacturer were operated at maximum torque and rotation speed under a water flow of 25 milliliters per minute. The authors made 6-millimeter long edge and groove cuts in 13-mm cross-section blocks using six medium-grit diamond burs for each handpiece. Each bur cut a total of 78 mm. The authors determined CR as the time to transect the block and analyzed the data by two-way analysis of variance with post hoc Scheffé tests. CRs varied by the type of cut and the number of spray ports. No differences were found in CRs for the three handpieces during edge cutting. The one-port handpiece cut significantly slower (P < .001) than did the three- and four-port handpieces during groove cutting. The data indicate that the number of handpiece spray ports, and their positioning relative to the bur affect water supply to the cutting interface and, consequently, the CR under these study conditions. Optimal cutting efficiency requires good coolant access, especially within restricted areas. A multiple-port handpiece may be advantageous when preparing the interproximal region for a crown or a proximal box, owing to the better water spray pattern. Dentists should consider the influence of the number of spray ports when selecting handpieces for cutting procedures.

Plate forming and break down pizza box

DOEpatents

Pantisano, Frank; Devine, Scott M.

1992-01-01

A standard corrugated paper pizza box is provided with slit cuts cut through the top panel of the pizza box in a shape to form four circular serving plates with a beveled raised edge and cross slit cuts through the bottom panel of the pizza box separating the box into four essentially equal portions for easy disposal.

Scientist-Educator Partnerships: the Cornerstone of Astrophysics E/PO

NASA Astrophysics Data System (ADS)

Meinke, Bonnie K.; Smith, Denise A.; Lawton, Brandon; Eisenhamer, Bonnie; Jirdeh, Hussein

2015-11-01

For nearly two decades, NASA has partnered scientists and educators by embedding Education and Public Outreach (E/PO) programs and funding in its science missions and research activities. This enables scientist and educators to work side-by-side in translating cutting-edge NASA science and technology for classrooms, museums, and public venues.The Office of Public Outreach at the Space Telescope Science Institute (STScI) is uniquely poised to foster collaboration between scientists with content expertise and educators with pedagogy expertise. As home to both Hubble Space Telescope and the future James Webb Space Telescope, STScI leverages the expertise of its scientists to create partnerships with its collocated Education Team to translate cutting-edge NASA science into new and effective learning tools. In addition, STScI is home of the NASA Science Mission Directorate (SMD) Astrophysics Science E/PO Forum, which facilitates connections both within the SMD E/PO community and beyond to scientists and educators across all NASA Astrophysics missions. These collaborations strengthen partnerships, build best practices, and enhance coherence for NASA SMD-funded E/PO missions and programs.We will present examples of astronomers’ engagement in our E/PO efforts, such as NASA Science4Girls.

Onco-nephrology: a decalogue.

PubMed

Cosmai, Laura; Porta, Camillo; Gallieni, Maurizio; Perazella, Mark A

2016-04-01

Onco-nephrology is an evolving subspecialty that focuses on the complex relationships existing between kidney and cancer. In this opinion piece, we propose a 'decalogue of onco-nephrology', in order to highlight the areas where the nephrologist and oncologist should work closely over the ensuing years to provide cutting-edge care for patients afflicted with cancer and kidney disease. The 10 points we have highlighted include (1) acute kidney injury and chronic kidney disease in cancer patients; (2) nephrotoxic effects of anticancer therapy, either traditional chemotherapeutics or novel molecularly targeted agents; (3) paraneoplastic renal manifestations; (4) management of patients nephrectomized for a kidney cancer; (5) renal replacement therapy and active oncological treatments; (6) kidney transplantation in cancer survivors and cancer risk in ESRD patients; (7) oncological treatment in kidney transplant patients; (8) pain management in patients with cancer and kidney disease, (9) development of integrated guidelines for onco-nephrology patients and (10) clinical trials designed specifically for onco-nephrology. Following these points, a multidisciplinary onco-nephrology team will be key to providing outstanding, cutting-edge care in both the acute and chronic setting to these patients. © The Author 2015. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

A Cutting-Edge Education: Incorporating Nano into the Undergraduate Curricula.

NASA Astrophysics Data System (ADS)

Zenner, Greta M.

2008-03-01

The Interdisciplinary Education Group (IEG) of the Materials Research Science and Engineering Center (MRSEC) on Nanostructured Interfaces at the University of Wisconsin-Madison (UW) develops and uses hands-on, interactive education and outreach materials to engage a variety of audiences in learning about nanotechnology and advanced materials. Many of the education products created are inspired by UW MRSEC research; and faculty, staff, and students regularly contribute to the IEG's work to share nanotechnology with a broader audience. The UW MRSEC has developed numerous teaching modules, labs, and education resources devoted to nanotechnology concepts, and many of these materials have been integrated into key introductory and advanced undergraduate courses at UW and other institutions, including small liberal arts colleges and community colleges. This effort has taken place through both the creation of new courses and the modification of existing courses to include cutting-edge content based on current research and emerging applications in nanotechnology. In this talk, I will present some of the new instructional materials we have developed based on advances in nanoscale science and technology, the implementation and integration of these materials into undergraduate curricula, and an overview of the UW MRSEC education efforts.

Accomplishing Transformative Research in a Challenging Fiscal Environment

NASA Astrophysics Data System (ADS)

Mitchell, E. J.; Paxton, L. J.; Bust, G.

2014-12-01

The shift in funding is forcing scientists to promise transformative research for a pittance. To accomplish this, researchers need to transform their methodology to include societal buy-in, use of commercial off-the-shelf (COTS) technology, and cross-discipline platform usage. As the cutting edge of research expands to view the system on the global scale with extremely fine resolution, fiscally reasonable budgets present a challenge to be met. Consider how do we measure a specific variable over 45-degrees of latitude in an isolated and hostile region of Earth - the total electron count over the South Pole? This work examines this transformative research using hosted payloads on buoys, balloons, and unmanned aerial vehicles (UAVs). We will show cutting edge research occurring simultaneous with education and public outreach, offering societal buy-in through interactive websites and student-built hosted payloads. These interactions provide a vision to the public and a new database to the scientists. The use of COTS technology and cross-discipline (oceanography and space) platforms keep the cost low. We will discuss a general methodology for accomplishing transformative research in a challenging fiscal environment through integration of COTS technology, assimilative and first principle models, and observing systems simulation experiments (OSSEs).

Applied breath analysis: an overview of the challenges and opportunities in developing and testing sensor technology for human health monitoring in aerospace and clinical applications

PubMed Central

Hunter, Gary W; Dweik, Raed A

2010-01-01

The aerospace industry requires the development of a range of chemical sensor technologies for such applications as leak detection, emission monitoring, fuel leak detection, environmental monitoring, and fire detection. A family of chemical sensors are being developed based on micromachining and microfabrication technology to fabricate microsensors with minimal size, weight, and power consumption, and the use of nanomaterials and structures to develop sensors with improved stability combined with higher sensitivity. However, individual sensors are limited in the amount of information that they can provide in environments that contain multiple chemical species. Thus, sensor arrays are being developed to address detection needs in such multi-species environments. These technologies and technical approaches have direct relevance to breath monitoring for clinical applications. This paper gives an overview of developing cutting-edge sensor technology and possible barriers to new technology implementation. This includes lessons learned from previous microsensor development, recent work in development of a breath monitoring system, and future directions in the implementation of cutting edge sensor technology. Clinical applications and the potential impact to the biomedical field of miniaturized smart gas sensor technology are discussed. PMID:20622933

High performance genetic algorithm for VLSI circuit partitioning

NASA Astrophysics Data System (ADS)

Dinu, Simona

2016-12-01

Partitioning is one of the biggest challenges in computer-aided design for VLSI circuits (very large-scale integrated circuits). This work address the min-cut balanced circuit partitioning problem- dividing the graph that models the circuit into almost equal sized k sub-graphs while minimizing the number of edges cut i.e. minimizing the number of edges connecting the sub-graphs. The problem may be formulated as a combinatorial optimization problem. Experimental studies in the literature have shown the problem to be NP-hard and thus it is important to design an efficient heuristic algorithm to solve it. The approach proposed in this study is a parallel implementation of a genetic algorithm, namely an island model. The information exchange between the evolving subpopulations is modeled using a fuzzy controller, which determines an optimal balance between exploration and exploitation of the solution space. The results of simulations show that the proposed algorithm outperforms the standard sequential genetic algorithm both in terms of solution quality and convergence speed. As a direction for future study, this research can be further extended to incorporate local search operators which should include problem-specific knowledge. In addition, the adaptive configuration of mutation and crossover rates is another guidance for future research.

Knowledge acquisition for medical diagnosis using collective intelligence.

PubMed

Hernández-Chan, G; Rodríguez-González, A; Alor-Hernández, G; Gómez-Berbís, J M; Mayer-Pujadas, M A; Posada-Gómez, R

2012-11-01

The wisdom of the crowds (WOC) is the process of taking into account the collective opinion of a group of individuals rather than a single expert to answer a question. Based on this assumption, the use of processes based on WOC techniques to collect new biomedical knowledge represents a challenging and cutting-edge trend on biomedical knowledge acquisition. The work presented in this paper shows a new schema to collect diagnosis information in Diagnosis Decision Support Systems (DDSS) based on collective intelligence and consensus methods.

Pilot study of manual sugarcane harvesting using biomechanical analysis.

PubMed

Clementson, C L; Hansen, A C

2008-07-01

In many countries, sugar cane harvesting is a very labor-intensive activity in which workers usually become fatigued after manually cutting the cane for a few hours. They need frequent pauses for rest, and they experience sustained injuries from excessive stress on the joints and muscles of the body. The cutting tool and motion involved directly influence the stresses created. A cutting tool that has not been designed by taking into consideration occupational biomechanics can lead to unnecessary strains in the body's muscle system, resulting in injuries. The purpose of this research was to carry out a pilot study of the impact of two common manual sugarcane cutting tools and the cutting posture they induce on the body with the aid of biomechanics. The machete and the cutlass from South Africa and Guyana, respectively, were examined to determine the cutting forces. Using static strength prediction modeling, the body stress levels at the point of cut in the cutting motion were determined. The cutting postures of three subjects were contrasted, their extreme postures were identified, and suggestions were made to improve the ergonomics of the cutting activity. The results of this pilot study showed that the cutlass required less cutting force than the machete because of the slicing cut provided by the curved blade edge of the cutlass. However, the biomechanical analysis indicated that the bent blade of the machete required less flexion of the back and therefore was likely to cause less back fatigue and injury. An improved design of the sugarcane manual harvesting tool should incorporate the bend of the machete to reduce flexion and a curved cutting edge that provides a slicing cut.

SU-E-T-501: Initial Orthovoltage Beam Profile Analysis of a Small Brass MLC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loughery, B; Snyder, M

2015-06-15

Purpose To create brass leaves for an orthovoltage MLC and take initial beam profile measurements. Methods The low-energy MLC was designed in previous work. Brass was chosen for its self-lubrication and low cost. Stock brass rectangles (30cm × 1.0cm × 0.5cm) were ordered with pre-cut gear rack along the topmost long edges. Leaf designs were translated into G-code, then cut with a Tormach CNC-1100 mill. Intense bowing was observed in the beam direction, which required straightening via an in-house jig. Straightened leaves were placed into MLC assembly and mounted to a 320 kVp orthovoltage tube. EDR2 film was irradiated inmore » four situations: MLC open so one edge was isocentric, and MLC open more than isocentric, completely closed MLC, and an open field shot with the MLC removed. The first two scans tested penumbra for our rectangular edges due to unfocused design. The final two scans tested transmission and interleaf leakage. All four experiments were set to 120 kVp and 10 mA for two minutes. Results Transmission and interleaf leakage were found to be zero. Interleaf leakage is faintly visible on film, but undetected by our film scanner despite high spatial resolution. Penumbra at isocenter was found to be 0.72mm, which matched the penumbras of true field edges. Penumbra off-isocenter was 1.1mm. Mechanically, leaves are moving smoothly once straightened. Conclusion Beam profiles through our brass MLC are acceptable. Leaves attenuate and move as designed. Looking forward, we intend to animate our MLC to deliver more complicated treatment plans.« less

Rapid fabrication of miniature lens arrays by four-axis single point diamond machining

PubMed Central

McCall, Brian; Tkaczyk, Tomasz S.

2013-01-01

A novel method for fabricating lens arrays and other non-rotationally symmetric free-form optics is presented. This is a diamond machining technique using 4 controlled axes of motion – X, Y, Z, and C. As in 3-axis diamond micro-milling, a diamond ball endmill is mounted to the work spindle of a 4-axis ultra-precision computer numerical control (CNC) machine. Unlike 3-axis micro-milling, the C-axis is used to hold the cutting edge of the tool in contact with the lens surface for the entire cut. This allows the feed rates to be doubled compared to the current state of the art of micro-milling while producing an optically smooth surface with very low surface form error and exceptionally low radius error. PMID:23481813

Chemical scissors cut phosphorene and their novel electronic properties

NASA Astrophysics Data System (ADS)

Peng, Xihong; Wei, Qun

2015-03-01

Phosphorene, a recently fabricated two-dimensional puckered honeycomb structure of black phosphorus, showed promising properties for applications in nano-electronics. In this work, we report a chemical scissors effect on phosphorene, using first principles density-functional methods. It was found that chemical species, such as H, OH, F, and Cl, can act as scissors to cut phosphorene. Phosphorus nanochains and nanoribbons can be obtained using such chemical scissors. The scissors effect results from the strong bonding between the chemical species and phosphorus atoms. Other species such as O, S and Se fail to cut phosphorene due to their weak bonding with phosphorus. The electronic structures of the produced P-chains reveal that the hydrogenated P-chain is an insulator; however, the pristine P-chain is a one-dimensional Dirac material, in which the charge carriers are massless fermions travelling at an effective speed of light approximately 8x105 m/s. The obtained zigzag phosphorene nanoribbons show either metallic or semiconducting behaviors, depending on the treatment of the edge phosphorus atoms.

Chemical scissors cut phosphorene nanostructures

NASA Astrophysics Data System (ADS)

Peng, Xihong; Wei, Qun

2014-12-01

Phosphorene, a recently fabricated two-dimensional puckered honeycomb structure of phosphorus, showed promising properties for applications in nano-electronics. In this work, we report a chemical scissors effect on phosphorene, using first-principles method. It was found that chemical species, such as H, OH, F, and Cl, can act as scissors to cut phosphorene. Phosphorus nanochains and nanoribbons can be obtained. The scissors effect results from the strong bonding between the chemical species and phosphorus atoms. Other species such as O, S and Se fail to cut phosphorene nanostructures due to their weak bonding with phosphorus. The electronic structures of the produced P-chains reveal that the hydrogenated chain is an insulator while the pristine chain is a one-dimensional Dirac material, in which the charge carriers are massless fermions travelling at an effective speed of light ˜8 × 105 m s-1. The obtained zigzag phosphorene nanoribbons show either metallic or semiconducting behaviors, depending on the treatment of the edge phosphorus atoms.

Monitoring morphology and hydrogen coverage of nanometric Pt/γ-Al2 O3 particles by in situ HERFD-XANES and quantum simulations.

PubMed

Gorczyca, Agnes; Moizan, Virginie; Chizallet, Celine; Proux, Olivier; Del Net, William; Lahera, Eric; Hazemann, Jean-Louis; Raybaud, Pascal; Joly, Yves

2014-11-10

Platinum nanoclusters highly dispersed on γ-alumina are widely used as heterogeneous catalysts. To understand the chemical interplay between the Pt nanoparticles, the support, and the reductive atmosphere, we performed X-ray absorption near edge structure (XANES) in situ experiments recorded in high energy resolution fluorescence detection (HERFD) mode. Spectra are assigned by comparison with simulated XANES spectra on models obtained by molecular dynamics (DFT-MD). We propose platinum cluster morphologies and quantify the hydrogen coverages compatible with XANES spectra recorded at variable hydrogen pressures and temperatures. Using cutting-edge methodologies to assign XANES spectra, this work gives unequalled atomic insights into the characterization of supported nanoclusters. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vertical-Control Subsystem for Automatic Coal Mining

NASA Technical Reports Server (NTRS)

Griffiths, W. R.; Smirlock, M.; Aplin, J.; Fish, R. B.; Fish, D.

1984-01-01

Guidance and control system automatically positions cutting drums of double-ended longwall shearer so they follow coal seam. System determines location of upper interface between coal and shale and continuously adjusts cutting-drum positions, upward or downward, to track undulating interface. Objective to keep cutting edges as close as practicable to interface and thus extract as much coal as possible from seam.

Predicting tool life in turning operations using neural networks and image processing

NASA Astrophysics Data System (ADS)

Mikołajczyk, T.; Nowicki, K.; Bustillo, A.; Yu Pimenov, D.

2018-05-01

A two-step method is presented for the automatic prediction of tool life in turning operations. First, experimental data are collected for three cutting edges under the same constant processing conditions. In these experiments, the parameter of tool wear, VB, is measured with conventional methods and the same parameter is estimated using Neural Wear, a customized software package that combines flank wear image recognition and Artificial Neural Networks (ANNs). Second, an ANN model of tool life is trained with the data collected from the first two cutting edges and the subsequent model is evaluated on two different subsets for the third cutting edge: the first subset is obtained from the direct measurement of tool wear and the second is obtained from the Neural Wear software that estimates tool wear using edge images. Although the complete-automated solution, Neural Wear software for tool wear recognition plus the ANN model of tool life prediction, presented a slightly higher error than the direct measurements, it was within the same range and can meet all industrial requirements. These results confirm that the combination of image recognition software and ANN modelling could potentially be developed into a useful industrial tool for low-cost estimation of tool life in turning operations.

The X-point effects on the peeling-ballooning stability conditions

NASA Astrophysics Data System (ADS)

Zheng, Linjin

2017-10-01

Due to the X-point singularity the safety factor tends to infinity as the last closed flux surface is approached. The usual numerical treatment of X-point singularity is to cut off a small fraction of edge region for system stability evaluation or simply use an up-down symmetric equilibrium without X-point included. This type of treatments have been used to make the peeling-ballooning stability diagram. We found that the mode types, peel or ballooning, can vary depending on how much the edge portion is cut off. When the cutting-off leads the edge safety factor (qa) to become close to a mode rational number, the peeling modes dominate; otherwise the ballooning type of modes prevail. The stability condition for peeling modes with qa being close to a rational number is much stringent than that for ballooning type of modes. Because qa tends to infinite near the separatrix, the mode rational surfaces are concentrated in the plasma region and thus the peeling modes are basically excluded. This extrapolation indicates that the stability boundary for high edge current, which is related to the peeling modes, need to be reexamined to take into account the X-point effects. Supported by U. S. Department of Energy, Office of Fusion Energy Science: Grant No. DE-FG02-04ER-54742.

Automated Laser Cutting In Three Dimensions

NASA Technical Reports Server (NTRS)

Bird, Lisa T.; Yvanovich, Mark A.; Angell, Terry R.; Bishop, Patricia J.; Dai, Weimin; Dobbs, Robert D.; He, Mingli; Minardi, Antonio; Shelton, Bret A.

1995-01-01

Computer-controlled machine-tool system uses laser beam assisted by directed flow of air to cut refractory materials into complex three-dimensional shapes. Velocity, position, and angle of cut varied. In original application, materials in question were thermally insulating thick blankets and tiles used on space shuttle. System shapes tile to concave or convex contours and cuts beveled edges on blanket, without cutting through outer layer of quartz fabric part of blanket. For safety, system entirely enclosed to prevent escape of laser energy. No dust generated during cutting operation - all material vaporized; larger solid chips dislodged from workpiece easily removed later.

Swept Mechanism of Micro-Milling Tool Geometry Effect on Machined Oxygen Free High Conductivity Copper (OFHC) Surface Roughness

PubMed Central

Shi, Zhenyu; Liu, Zhanqiang; Li, Yuchao; Qiao, Yang

2017-01-01

Cutting tool geometry should be very much considered in micro-cutting because it has a significant effect on the topography and accuracy of the machined surface, particularly considering the uncut chip thickness is comparable to the cutting edge radius. The objective of this paper was to clarify the influence of the mechanism of the cutting tool geometry on the surface topography in the micro-milling process. Four different cutting tools including two two-fluted end milling tools with different helix angles of 15° and 30° cutting tools, as well as two three-fluted end milling tools with different helix angles of 15° and 30° were investigated by combining theoretical modeling analysis with experimental research. The tool geometry was mathematically modeled through coordinate translation and transformation to make all three cutting edges at the cutting tool tip into the same coordinate system. Swept mechanisms, minimum uncut chip thickness, and cutting tool run-out were considered on modeling surface roughness parameters (the height of surface roughness Rz and average surface roughness Ra) based on the established mathematical model. A set of cutting experiments was carried out using four different shaped cutting tools. It was found that the sweeping volume of the cutting tool increases with the decrease of both the cutting tool helix angle and the flute number. Great coarse machined surface roughness and more non-uniform surface topography are generated when the sweeping volume increases. The outcome of this research should bring about new methodologies for micro-end milling tool design and manufacturing. The machined surface roughness can be improved by appropriately selecting the tool geometrical parameters. PMID:28772479

Influence of a falling edge on high power microwave pulse combination

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jiawei; Huang, Wenhua; Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024

This paper presents an explanation of the influence of a microwave falling edge on high-power microwave pulse combination. Through particle-in-cell simulations, we discover that the falling edge is the driving factor that limits the output power of the combined pulses. We demonstrate that the space charge field, which accumulates to become comparable to the E-field at the falling edge of the former pulse, will trap the electrons in the gas layer and decrease its energy to attain a high ionization rate. Hence, avalanche discharge, caused by trapped electrons, makes the plasma density to approach the critical density and cuts offmore » the latter microwave pulse. An X-band combination experiment is conducted with different pulse intervals. This experiment confirms that the high density plasma induced by the falling edge can cut off the latter pulse, and that the time required for plasma recombination in the transmission channel is several microseconds. To ensure a high output power for combined pulses, the latter pulse should be moved ahead of the falling edge of the former one, and consequently, a beat wave with high peak power becomes the output by adding two pulses with normal amplitudes.« less

Influence of a falling edge on high power microwave pulse combination

NASA Astrophysics Data System (ADS)

Li, Jiawei; Huang, Wenhua; Zhu, Qi; Xiao, Renzhen; Shao, Hao

2016-07-01

This paper presents an explanation of the influence of a microwave falling edge on high-power microwave pulse combination. Through particle-in-cell simulations, we discover that the falling edge is the driving factor that limits the output power of the combined pulses. We demonstrate that the space charge field, which accumulates to become comparable to the E-field at the falling edge of the former pulse, will trap the electrons in the gas layer and decrease its energy to attain a high ionization rate. Hence, avalanche discharge, caused by trapped electrons, makes the plasma density to approach the critical density and cuts off the latter microwave pulse. An X-band combination experiment is conducted with different pulse intervals. This experiment confirms that the high density plasma induced by the falling edge can cut off the latter pulse, and that the time required for plasma recombination in the transmission channel is several microseconds. To ensure a high output power for combined pulses, the latter pulse should be moved ahead of the falling edge of the former one, and consequently, a beat wave with high peak power becomes the output by adding two pulses with normal amplitudes.

Finite Element Simulation of Machining of Ti6Al4V Alloy

NASA Astrophysics Data System (ADS)

Rizzuti, S.; Umbrello, D.

2011-05-01

Titanium and its alloys are an important class of materials, especially for aerospace applications, due to their excellent combination of strength and fracture toughness as well as low density. However, these materials are generally regarded as difficult to machine because of their low thermal conductivity and high chemical reactivity with cutting tool materials. Moreover, the low thermal conductivity of Titanium inhibits dissipation of heat within the workpiece causing an higher temperature at the cutting edge and generating for higher cutting speed a rapid chipping at the cutting edge which leads to catastrophic failure. In addition, chip morphology significantly influences the thermo-mechanical behaviour at the workpiece/tool interface, which also affects the tool life. In this paper a finite element analysis of machining of TiAl6V4 is presented. In particular, cutting force, chip morphology and segmentation are taken into account due to their predominant roles to determine machinability and tool wear during the machining of these alloys. Results in terms of residual stresses are also presented. Moreover, the numerical results are compared with experimental ones.

Women's technical and professional symposium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Budil, K; Mack, L

1999-10-01

This is the fourth LLNL-sponsored Women's Technical and Professional Symposium. This year's theme: ''Excellence through the Millennium,'' focuses on the cutting edge work being done at LLNL and the many contributions of women to our science and technology mission. We hope this Symposium gives each person attending a better idea of the broad scope of the Laboratory's mission and their place within the organization. It is easy to lose sight of the fact that we all work in support of science and technology despite the diversity of our experience. This Symposium provides an opportunity to reflect on our past andmore » to begin to plan our future.« less

The geometry of the cutting front created by Fibre and CO2 lasers when profiling stainless steel under standard commercial conditions

NASA Astrophysics Data System (ADS)

Pocorni, Jetro; Powell, John; Frostevarg, Jan; Kaplan, Alexander F. H.

2018-07-01

Cutting fronts created by CO2 and fibre lasers in stainless steel at thicknesses between 2 mm and 10 mm have been 'frozen' and their geometry has been measured. Standard commercial cutting parameters were used to generate the cuts for both types of laser. The resulting three-dimensional cutting front shapes have been curve fitted as polynomials and semicircles. Various features of the cutting front geometry are discussed including the lack of correlation of the cut front inclination with either the relevant Brewster angle or the inclination of the striations on the cut edge.

A comparative study on performance of CBN inserts when turning steel under dry and wet conditions

NASA Astrophysics Data System (ADS)

Abdullah Bagaber, Salem; Razlan Yusoff, Ahmad

2017-10-01

Cutting fluids is the most unsustainable components of machining processes, it is negatively impacting on the environmental and additional energy required. Due to its high strength and corrosion resistance, the machinability of stainless steel has attracted considerable interest. This study aims to evaluate performance of cubic boron nitride (CBN) inserts for the machining parameters includes the power consumption and surface roughness. Due to the high single cutting-edge cost of CBN, the performance of significant is importance for hard finish turning. The present work also deals with a comparative study on power consumption and surface roughness under dry and flood conditions. Turning process of the stainless steel 316 was performed. A response surface methodology based box-behnken design (BBD) was utilized for statistical analysis. The optimum process parameters are determined as the overall performance index. The comparison study has been done between dry and wet stainless-steel cut in terms of minimum value of energy and surface roughness. The result shows the stainless still can be machined under dry condition with 18.57% improvement of power consumption and acceptable quality compare to the wet cutting. The CBN tools under dry cutting stainless steel can be used to reduce the environment impacts in terms of no cutting fluid use and less energy required which is effected in machining productivity and profit.

Modelling and simulation of effect of ultrasonic vibrations on machining of Ti6Al4V.

PubMed

Patil, Sandip; Joshi, Shashikant; Tewari, Asim; Joshi, Suhas S

2014-02-01

The titanium alloys cause high machining heat generation and consequent rapid wear of cutting tool edges during machining. The ultrasonic assisted turning (UAT) has been found to be very effective in machining of various materials; especially in the machining of "difficult-to-cut" material like Ti6Al4V. The present work is a comprehensive study involving 2D FE transient simulation of UAT in DEFORM framework and their experimental characterization. The simulation shows that UAT reduces the stress level on cutting tool during machining as compared to that of in continuous turning (CT) barring the penetration stage, wherein both tools are subjected to identical stress levels. There is a 40-45% reduction in cutting forces and about 48% reduction in cutting temperature in UAT over that of in CT. However, the reduction magnitude reduces with an increase in the cutting speed. The experimental analysis of UAT process shows that the surface roughness in UAT is lower than in CT, and the UATed surfaces have matte finish as against the glossy finish on the CTed surfaces. Microstructural observations of the chips and machined surfaces in both processes reveal that the intensity of thermal softening and shear band formation is reduced in UAT over that of in CT. Copyright © 2013 Elsevier B.V. All rights reserved.

Slice-push, formation of grooves and the scale effect in cutting.

PubMed

Atkins, A G

2016-06-06

Three separate aspects of cutting are investigated which complement other papers on the mechanics of separation processes presented at this interdisciplinary Theo Murphy meeting. They apply in all types of cutting whether blades are sharp or blunt, and whether the material being cut is 'hard, stiff and strong' or 'soft, compliant and weak'. The first topic discusses why it is easier to cut when there is motion along (parallel to) the blade as well motion across (perpendicular to) the cutting edge, and the analysis is applied to optimization of blade geometries to produce minimum cutting forces and hence minimum damage to cut surfaces. The second topic concerns cutting with more than one edge with particular application to the formation of grooves in surfaces by hard pointed tools. The mechanics are investigated and applied to the topic of abrasive wear by hard particles. Traditional analyses say that abrasive wear resistance increases monotonically with the hardness of the workpiece, but we show that the fracture toughness of the surface material is also important, and that behaviour is determined by the toughness-to-hardness ratio rather than hardness alone. Scaling forms the third subject. As cutting is a branch of elasto-plastic fracture mechanics, cube-square energy scaling applies in which the important length scale is (ER/k (2)), where E is Young's modulus, R is the fracture toughness and k is the shear yield strength. Whether, in cutting, material is removed as ductile ribbons, as semi-ductile discontinuous chips, or by brittle 'knocking lumps out' is shown to depend on the depth of cut relative to this characteristic length parameter. Scaling in biology is called allometry and its relationship with engineering scaling is discussed. Some speculative predictions are made in relation to the action of teeth on food.

On brain activity mapping: insights and lessons from Brain Decoding Project to map memory patterns in the hippocampus.

PubMed

Tsien, Joe Z; Li, Meng; Osan, Remus; Chen, Guifen; Lin, Longnian; Wang, Phillip Lei; Frey, Sabine; Frey, Julietta; Zhu, Dajiang; Liu, Tianming; Zhao, Fang; Kuang, Hui

2013-09-01

The BRAIN project recently announced by the president Obama is the reflection of unrelenting human quest for cracking the brain code, the patterns of neuronal activity that define who we are and what we are. While the Brain Activity Mapping proposal has rightly emphasized on the need to develop new technologies for measuring every spike from every neuron, it might be helpful to consider both the theoretical and experimental aspects that would accelerate our search for the organizing principles of the brain code. Here we share several insights and lessons from the similar proposal, namely, Brain Decoding Project that we initiated since 2007. We provide a specific example in our initial mapping of real-time memory traces from one part of the memory circuit, namely, the CA1 region of the mouse hippocampus. We show how innovative behavioral tasks and appropriate mathematical analyses of large datasets can play equally, if not more, important roles in uncovering the specific-to-general feature-coding cell assembly mechanism by which episodic memory, semantic knowledge, and imagination are generated and organized. Our own experiences suggest that the bottleneck of the Brain Project is not only at merely developing additional new technologies, but also the lack of efficient avenues to disseminate cutting edge platforms and decoding expertise to neuroscience community. Therefore, we propose that in order to harness unique insights and extensive knowledge from various investigators working in diverse neuroscience subfields, ranging from perception and emotion to memory and social behaviors, the BRAIN project should create a set of International and National Brain Decoding Centers at which cutting-edge recording technologies and expertise on analyzing large datasets analyses can be made readily available to the entire community of neuroscientists who can apply and schedule to perform cutting-edge research.

Microwave assisted hard rock cutting

DOEpatents

Lindroth, David P.; Morrell, Roger J.; Blair, James R.

1991-01-01

An apparatus for the sequential fracturing and cutting of subsurface volume of hard rock (102) in the strata (101) of a mining environment (100) by subjecting the volume of rock to a beam (25) of microwave energy to fracture the subsurface volume of rock by differential expansion; and , then bringing the cutting edge (52) of a piece of conventional mining machinery (50) into contact with the fractured rock (102).

Growing Cutting-edge X-ray Optics

ScienceCinema

Conley, Ray

2018-03-02

Ever imagined that an Xbox controller could help open a window into a world spanning just one billionth of a meter? Brookhaven Lab's Ray Conley grows cutting-edge optics called multilayer Laue lenses (MLL) one atomic layer at a time to focus high-energy x-rays to within a single nanometer. To achieve this focusing feat, Ray uses a massive, custom-built atomic deposition device, an array of computers, and a trusty Xbox controller. These lenses will be deployed at the Lab's National Synchrotron Light Source II, due to begin shining super-bright light on pressing scientific puzzles in 2015.

Educators on the Edge: Big Ideas for Change and Innovation. Australian College of Educators (ACE) National Conference Proceedings (Brisbane, Australia, September 24-25, 2015)

ERIC Educational Resources Information Center

Finger, Glenn, Ed.; Ghirelli, Paola S., Ed.

2015-01-01

The 2015 Australian College of Educators (ACE) National Conference theme is "Educators on the Edge: Big Ideas for Change and Innovation." ACE presented an opportunity for all education professionals to gather, discuss, and share cutting-edge, creative and innovative practices, nationally and globally at the conference held on September…

Mobil Solar Energy Corporation thin EFG octagons. Semiannual subcontract report, 1 April 1992--30 September 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalejs, J.P.

1993-09-01

This report describes work carried out for the PVMaT program at Mobil Solar for the period covering April 1, 1992, to September 30, 1992. Mobil Solar is developing advanced technology for growing and cutting 200-{mu}m-thick edge-defined film-fed growth (EFG) octagon tubes that will reduce the manufacturing costs of 10-cm {times} 10-cm polycrystalline EFG silicon wafers. Mobil Solar has made progress in identifying factors that impact on thickness nonuniformity and means to reduce the deleterious impact of ambient-related effects that have caused reduction in crystal growth productivity and wafer yield. The current main obstacle to meeting material yield targets arises duemore » to the buckling produced by thermal stress. Studies of laser cutting of EFG silicon using ND:YAG and dye lasers are underway to develop reduced damage cutting methods. Mobil Solar has carried out design reviews for crystal growth and laser cutting equipment. A task has been initiated to evaluate new online sensors for crystal growth process control and to study implementation of advanced control concepts for productivity and yield improvements.« less

Usewear studies of flint tools with microPIXE and microRBS

NASA Astrophysics Data System (ADS)

Christensen, Marianne; Grime, Geoff; Menu, Michel; Walter, Philippe

1993-05-01

The use of ancient stone tools leaves a polish (usewear) on the cutting edge which can be studied to determine the material the tool had worked during its use. The film is formed by high pressure intrusion of the worked material into the microcavities of the chipped flint surface and so the film can also be analysed directly to determine the nature of the worked material. This paper describes the analysis of experimental flint tools which had worked bone and ivory using microbeam PIXE and RBS. It is found that PIXE used simultaneously with RBS allows the thickness and composition of the film to be determined and ivory distinguished from bone while RBS mapping allows the three-dimensional structure of the film to be determined.

Experiences in implementing uHTS--cutting edge technology meets the real world.

PubMed

Gribbon, Philip; Schaertl, Sabine; Wickenden, Malcolm; Williams, Gareth; Grimley, Rachel; Stuhmeier, Frank; Preckel, Hartwig; Eggeling, Christian; Kraemer, Joachim; Everett, Jeremy; Keighley, Wilma W; Sewing, Andreas

2004-01-01

Driven by growing corporate compound files, the demands of target biology, and attempts to cut cost, the number of solutions to HTS has spiralled. In quick succession new assay technologies and screening platforms are appearing on the market, with the promise of screening faster than ever in low volume high density formats whilst providing high quality data. Within this world of rapid change, Pfizer has applied cutting edge technology to HTS by introducing screening in 1 microl formats utilising single molecule detection technology. Instead of resource intensive in-house development, Pfizer entered into a collaboration with Evotec OAI / Evotec Technologies and introduced their Mark-II EVOscreen platform. In this article we will outline the benefits of the approach taken at Pfizer, Sandwich, and introduce the Mark-II EVOscreen platform, illustrating the potential but also possible pitfalls of HTS miniaturisation.

Microfabricated instrument for tissue biopsy and analysis

DOEpatents

Krulevitch, Peter A.; Lee, Abraham P.; Northrup, M. Allen; Benett, William J.

2001-01-01

A microfabricated biopsy/histology instrument which has several advantages over the conventional procedures, including minimal specimen handling, smooth cutting edges with atomic sharpness capable of slicing very thin specimens (approximately 2 .mu.m or greater), micro-liter volumes of chemicals for treating the specimens, low cost, disposable, fabrication process which renders sterile parts, and ease of use. The cutter is a "cheese-grater" style design comprising a block or substrate of silicon and which uses anisotropic etching of the silicon to form extremely sharp and precise cutting edges. As a specimen is cut, it passes through the silicon cutter and lies flat on a piece of glass which is bonded to the cutter. Microchannels are etched into the glass or silicon substrates for delivering small volumes of chemicals for treating the specimen. After treatment, the specimens can be examined through the glass substrate.

Investigation of the Hydraulic Characteristics of Capillary Elements of the Injector Head of Jet Engines under Conditions of Isothermal Flow of A Liquid

NASA Astrophysics Data System (ADS)

Nigodjuk, V. E.; Sulinov, A. V.

2018-01-01

The article presents the results of an experimental study of the hydraulic characteristics of capillary elements of the injector head of jet engines in isothermal fluid flow and the proposed method of their calculation. The main geometric dimensions of the capillaries in the experiment were changed in the following range: Inner diameter from 0.16 to 0.36 mm, length from 4.3 to 158 mm and relative length from 25 to 614 and the inlet edge of the capillaries: sharp or smooth the leading edge. As the working fluid during the tests were distilled water, acetone and ethyl alcohol. Based on the results of a study of the dependences for calculation of ultimate losses in laminar and turbulent flow regimes in capillary tubes with smooth and sharp edges input. The influence of surface tension forces on loss of input on a sharp cutting edge. Experimentally confirmed the possibility of calculating the linear coefficient of hydraulic resistance of capillary tubes with a diameter of 0.16-0.36 mm in isothermal stable during the known dependencies that are valid for hydrodynamically smooth round tube.

Positive edge effects on forest-interior cryptogams in clear-cuts.

PubMed

Caruso, Alexandro; Rudolphi, Jörgen; Rydin, Håkan

2011-01-01

Biological edge effects are often assessed in high quality focal habitats that are negatively influenced by human-modified low quality matrix habitats. A deeper understanding of the possibilities for positive edge effects in matrix habitats bordering focal habitats (e.g. spillover effects) is, however, essential for enhancing landscape-level resilience to human alterations. We surveyed epixylic (dead wood inhabiting) forest-interior cryptogams (lichens, bryophytes, and fungi) associated with mature old-growth forests in 30 young managed Swedish boreal forest stands bordering a mature forest of high conservation value. In each young stand we registered species occurrences on coarse dead wood in transects 0-50 m from the border between stand types. We quantified the effect of distance from the mature forest on the occurrence of forest-interior species in the young stands, while accounting for local environment and propagule sources. For comparison we also surveyed epixylic open-habitat (associated with open forests) and generalist cryptogams. Species composition of epixylic cryptogams in young stands differed with distance from the mature forest: the frequency of occurrence of forest-interior species decreased with increasing distance whereas it increased for open-habitat species. Generalists were unaffected by distance. Epixylic, boreal forest-interior cryptogams do occur in matrix habitats such as clear-cuts. In addition, they are associated with the matrix edge because of a favourable microclimate closer to the mature forest on southern matrix edges. Retention and creation of dead wood in clear-cuts along the edges to focal habitats is a feasible way to enhance the long-term persistence of epixylic habitat specialists in fragmented landscapes. The proposed management measures should be performed in the whole stand as it matures, since microclimatic edge effects diminish as the matrix habitat matures. We argue that management that aims to increase habitat quality in matrix habitats bordering focal habitats should increase the probability of long-term persistence of habitat specialists.

Positive Edge Effects on Forest-Interior Cryptogams in Clear-Cuts

PubMed Central

Caruso, Alexandro; Rudolphi, Jörgen; Rydin, Håkan

2011-01-01

Biological edge effects are often assessed in high quality focal habitats that are negatively influenced by human-modified low quality matrix habitats. A deeper understanding of the possibilities for positive edge effects in matrix habitats bordering focal habitats (e.g. spillover effects) is, however, essential for enhancing landscape-level resilience to human alterations. We surveyed epixylic (dead wood inhabiting) forest-interior cryptogams (lichens, bryophytes, and fungi) associated with mature old-growth forests in 30 young managed Swedish boreal forest stands bordering a mature forest of high conservation value. In each young stand we registered species occurrences on coarse dead wood in transects 0–50 m from the border between stand types. We quantified the effect of distance from the mature forest on the occurrence of forest-interior species in the young stands, while accounting for local environment and propagule sources. For comparison we also surveyed epixylic open-habitat (associated with open forests) and generalist cryptogams. Species composition of epixylic cryptogams in young stands differed with distance from the mature forest: the frequency of occurrence of forest-interior species decreased with increasing distance whereas it increased for open-habitat species. Generalists were unaffected by distance. Epixylic, boreal forest-interior cryptogams do occur in matrix habitats such as clear-cuts. In addition, they are associated with the matrix edge because of a favourable microclimate closer to the mature forest on southern matrix edges. Retention and creation of dead wood in clear-cuts along the edges to focal habitats is a feasible way to enhance the long-term persistence of epixylic habitat specialists in fragmented landscapes. The proposed management measures should be performed in the whole stand as it matures, since microclimatic edge effects diminish as the matrix habitat matures. We argue that management that aims to increase habitat quality in matrix habitats bordering focal habitats should increase the probability of long-term persistence of habitat specialists. PMID:22114728

Wear Mechanism of Chemical Vapor Deposition (CVD) Carbide Insert in Orthogonal Cutting Ti-6Al-4V ELI at High Cutting Speed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gusri, A. I.; Che Hassan, C. H.; Jaharah, A. G.

2011-01-17

The performance of Chemical Vapor Deposition (CVD) carbide insert with ISO designation of CCMT 12 04 04 LF, when turning titanium alloys was investigated. There were four layers of coating materials for this insert i.e.TiN-Al2O3-TiCN-TiN. The insert performance was evaluated based on the insert's edge resistant towards the machining parameters used at high cutting speed range of machining Ti-6Al-4V ELI. Detailed study on the wear mechanism at the cutting edge of CVD carbide tools was carried out at cutting speed of 55-95 m/min, feed rate of 0.15-0.35 mm/rev and depth of cut of 0.10-0.20 mm. Wear mechanisms such as abrasivemore » and adhesive were observed on the flank face. Crater wear due to diffusion was also observed on the rake race. The abrasive wear occurred more at nose radius and the fracture on tool were found at the feed rate of 0.35 mm/rev and the depth of cut of 0.20 mm. The adhesion wear takes place after the removal of the coating or coating delaminating. Therefore, adhesion or welding of titanium alloy onto the flank and rake faces demonstrates a strong bond at the workpiece-tool interface.« less

Wear Mechanism of Chemical Vapor Deposition (CVD) Carbide Insert in Orthogonal Cutting Ti-6Al-4V ELI at High Cutting Speed

NASA Astrophysics Data System (ADS)

Gusri, A. I.; Che Hassan, C. H.; Jaharah, A. G.

2011-01-01

The performance of Chemical Vapor Deposition (CVD) carbide insert with ISO designation of CCMT 12 04 04 LF, when turning titanium alloys was investigated. There were four layers of coating materials for this insert i.e.TiN-Al2O3-TiCN-TiN. The insert performance was evaluated based on the insert's edge resistant towards the machining parameters used at high cutting speed range of machining Ti-6Al-4V ELI. Detailed study on the wear mechanism at the cutting edge of CVD carbide tools was carried out at cutting speed of 55-95 m/min, feed rate of 0.15-0.35 mm/rev and depth of cut of 0.10-0.20 mm. Wear mechanisms such as abrasive and adhesive were observed on the flank face. Crater wear due to diffusion was also observed on the rake race. The abrasive wear occurred more at nose radius and the fracture on tool were found at the feed rate of 0.35 mm/rev and the depth of cut of 0.20 mm. The adhesion wear takes place after the removal of the coating or coating delaminating. Therefore, adhesion or welding of titanium alloy onto the flank and rake faces demonstrates a strong bond at the workpiece-tool interface.

A new method to measure circular runout of end-milling spindle based on cutting mark

NASA Astrophysics Data System (ADS)

Zhou, Jianlai; Liu, Shuchun

2008-12-01

A practical method is introduced to measure the circular runout of a end-milling spindle system at high speed rotations without the need of a reference sphere. A workpiece is held on a linear slide which moves along the axial direction of the spindle. The spindle is then programmed to run at a specific speed. A very sharp edge cutter must be used and the depth of cut will be very shallow in order to keep the cutting force very small. The workpiece is then fed into the end mill in order to make a cutting mark of teens μm in depth. The cutting marks are circular, and their diameters are related to the circular runout of the spindle system. The cutting mark that is generated at a specific speed is expected to contain information about the spindle circular runout at this speed. In practice the cutting marks are not perfectly circular. Therefore, a best-fit circle of a cutting mark is needed to determine its diameter. A high-resolution edge detector machine is used for this purpose. Quantitative precision analysis was carried out to confirm the accuracy and repeatability of this new measurement technique. It is demonstrated that this technique for the measurement of spindle circular runout is an effective tool in verifying the actual running accuracy of spindles at their actual operating speeds and can be accomplished without the need for a reference sphere.

Cutting boards in Salmonella cross-contamination.

PubMed

Cliver, Dean O

2006-01-01

Cutting boards are commonly perceived as important fomites in cross-contamination of foods with agents such as Salmonella spp., despite the lack of supporting epidemiological data. A variety of woods and plastics have been used to make work surfaces for cutting. In general, wood is said to dull knives less than plastic, and plastic is seen as less porous than wood. Research to model the hypothetical cross-contamination has been done in a variety of ways and has yielded a variety of results. At least some of the work with knife-scarred plastic indicates that the surface is very difficult to clean and disinfect, although this may vary among the polymers used. High-density polyethylene, which is most used in commercial applications, has been shown to delaminate in response to knife scarring. Wood is intrinsically porous, which allows food juices and bacteria to enter the body of the wood unless a highly hydrophobic residue covers the surface. The moisture is drawn in by capillary action until there is no more free fluid on the surface, at which point immigration ceases. Bacteria in the wood pores are not killed instantly, but neither do they return to the surface. Destructive sampling reveals infectious bacteria for hours, but resurrection of these bacteria via knife edges has not been demonstrated. Small plastic cutting boards can be cleaned in a dishwasher (as can some specially treated wooden boards), but the dishwasher may distribute the bacteria onto other food-contact surfaces. Most small wooden boards (i.e., those with no metal joiners in them) can be sterilized in a microwave oven, but this should be unnecessary if accumulation of food residues is prevented. However, 2 epidemiological studies seem to show that cutting board cleaning habits have little influence on the incidence of sporadic salmonellosis. Further, one of these studies indicated that use of plastic cutting boards in home kitchens is hazardous, whereas use of wooden cutting boards is not.

A Star on Earth

ScienceCinema

Prager, Stewart; Zwicker, Andrew; Hammet, Greg; Tresemer, Kelsey; Diallo, Ahmed

2018-02-14

At the Energy Department's Princeton Plasma Physics Lab, scientists are trying to accomplish what was once considered the realm of science fiction: create a star on Earth. The National Spherical Torus Experiment (NSTX) is a magnetic fusion device that is used to study the physics principles of spherically shaped plasmas -- hot ionized gases in which, under the right conditions, nuclear fusion will occur. Fusion is the energy source of the sun and all of the stars. Not just limited to theoretical work, the NSTX is enabling cutting-edge research to develop fusion as a future energy source.

Administrator Bolden visits Ames on This Week @NASA – February 19, 2016

NASA Image and Video Library

2016-02-19

NASA Administrator Charles Bolden visited Ames Research Center at Moffett Field, California to thank employees for the work they do on behalf of the agency to improve aviation. President Obama’s Fiscal Year 2017 budget proposal for NASA calls for a multi-year investment in aeronautics research that will enable the agency to test, demonstrate and validate cutting-edge technologies designed to make aviation cleaner, greener, safer, and quieter. Also, Cygnus leaves the space station, New astrophysics mission, X-ray astronomy mission launches, and NEAR Shoemaker anniversary!

Support of Integrated Health Management (IHM) through Automated Analyses of Flowfield-Derived Spectrographic Data

NASA Technical Reports Server (NTRS)

Patrick, Marshall C.; Cooper, Anita E.; Powers, W. T.

2003-01-01

Flow-field analysis techniques under continuing development at NASA's Marshall Space Flight Center are the foundation for a new type of health monitoring instrumentation for propulsion systems and a vast range of other applications. Physics, spectroscopy, mechanics, optics, and cutting-edge computer sciences merge to make recent developments in such instrumentation possible. Issues encountered in adaptation of such a system to future space vehicles, or retrofit in existing hardware, are central to the work. This paper is an overview of the collaborative efforts results, current efforts, and future plans.

FY2014 Electric Drive Technologies Annual Progress Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

The Electric Drive Technologies research and development (R&D) subprogram within the DOE Vehicle Technologies Office (VTO) provides support and guidance for many cutting-edge automotive technologies under development. Research is focused on developing power electronics (PE), electric motor, and traction drive system (TDS) technologies that will reduce system cost and improve their efficiency in transforming battery energy to useful work. The R&D is also aimed at better understanding and improving how various components of tomorrow’s automobiles will function as a unified system to improve fuel efficiency.

FY2016 Electric Drive Technologies Annual Progress Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

The Electric Drive Technologies research and development (R&D) subprogram within the DOE Vehicle Technologies Office (VTO) provides support and guidance for many cutting-edge automotive technologies under development. Research is focused on developing power electronics (PE), electric motor, and traction drive system (TDS) technologies that will reduce system cost and improve their efficiency in transforming battery energy to useful work. The R&D is also aimed at better understanding and improving how various components of tomorrow’s automobiles will function as a unified system to improve fuel efficiency.

FY2015 Electric Drive Technologies Annual Progress Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

The Electric Drive Technologies research and development (R&D) subprogram within the DOE Vehicle Technologies Office (VTO) provides support and guidance for many cutting-edge automotive technologies under development. Research is focused on developing power electronics (PE), electric motor, and traction drive system (TDS) technologies that will reduce system cost and improve their efficiency in transforming battery energy to useful work. The R&D is also aimed at better understanding and improving how various components of tomorrow’s automobiles will function as a unified system to improve fuel efficiency.

Airport electrotechnology resource guide. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geba, V.; Nesbit, M.

1998-06-01

Electrotechnologies offer utilities a cutting edge marketing tool to work with airport customers to increase passenger comfort, and achieve environmental and economic goals. At the same time, utility objectives such as customer retention, and revenue and sales goals can be enhanced. This guide provides electric utility marketing staff with the necessary information to market electrotechnologies in airport applications. The airport industry is profiled and an overview of airport building, infrastructure technologies and electric vehicles is provided. In addition, the guide offers market strategies for customer targeting, market research, market plan development and development of trade ally partnerships.

Hearing in True 3-D

NASA Technical Reports Server (NTRS)

2004-01-01

In 1984, researchers from Ames Research Center came together to develop advanced human interfaces for NASA s teleoperations that would come to be known as "virtual reality." The basis of the work theorized that if the sensory interfaces met a certain threshold and sufficiently supported each other, then the operator would feel present in the remote/synthetic environment, rather than present in their physical location. Twenty years later, this prolific research continues to pay dividends to society in the form of cutting-edge virtual reality products, such as an interactive audio simulation system.

Foundational Tools for Petascale Computing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Barton

2014-05-19

The Paradyn project has a history of developing algorithms, techniques, and software that push the cutting edge of tool technology for high-end computing systems. Under this funding, we are working on a three-year agenda to make substantial new advances in support of new and emerging Petascale systems. The overall goal for this work is to address the steady increase in complexity of these petascale systems. Our work covers two key areas: (1) The analysis, instrumentation and control of binary programs. Work in this area falls under the general framework of the Dyninst API tool kits. (2) Infrastructure for building toolsmore » and applications at extreme scale. Work in this area falls under the general framework of the MRNet scalability framework. Note that work done under this funding is closely related to work done under a contemporaneous grant, “High-Performance Energy Applications and Systems”, SC0004061/FG02-10ER25972, UW PRJ36WV.« less

44 CFR 63.17 - Procedures and data requirements for imminent collapse certifications by States.

Code of Federal Regulations, 2010 CFR

2010-10-01

... forth. (i) Top edge of bluff (cliff top). (ii) Top edge of escarpment on an eroding dune (i.e., a nearly vertical erosional cut at the seaward face of the dune). The normal high tide should be near the toe of the... high bluff or dune and not accessible from the water side, the top edge of the bluff or dune will be...

Product surface hardening in non-self-sustained glow discharge plasma before synthesis of superhard coatings

NASA Astrophysics Data System (ADS)

Krasnov, P. S.; Metel, A. S.; Nay, H. A.

2017-05-01

Before the synthesis of superhard coating, the product surface is hardened by means of plasma nitriding, which prevents the surface deformations and the coating brittle rupture. The product heating by ions accelerated from plasma by applied to the product bias voltage leads to overheating and blunting of the product sharp edges. To prevent the blunting, it is proposed to heat the products with a broad beam of fast nitrogen molecules. The beam injection into a working vacuum chamber results in filling of the chamber with quite homogeneous plasma suitable for nitriding. Immersion in the plasma of the electrode and heightening of its potential up to 50-100 V initiate a non-self-sustained glow discharge between the electrode and the chamber. It enhances the plasma density by an order of magnitude and reduces its spatial nonuniformity down to 5-10%. When a cutting tool is isolated from the chamber, it is bombarded by plasma ions with an energy corresponding to its floating potential, which is lower than the sputtering threshold. Hence, the sharp edges are sputtered only by fast nitrogen molecules with the same rate as other parts of the tool surface. This leads to sharpening of the cutting tools instead of blunting.

Nanometric edge profile measurement of cutting tools on a diamond turning machine

NASA Astrophysics Data System (ADS)

Asai, Takemi; Arai, Yoshikazu; Cui, Yuguo; Gao, Wei

2008-10-01

Single crystal diamond tools are used for fabrication of precision parts [1-5]. Although there are many types of tools that are supplied, the tools with round nose are popular for machining very smooth surfaces. Tools with small nose radii, small wedge angles and included angles are also being utilized for fabrication of micro structured surfaces such as microlens arrays [6], diffractive optical elements and so on. In ultra precision machining, tools are very important as a part of the machining equipment. The roughness or profile of machined surface may become out of desired tolerance. It is thus necessary to know the state of the tool edge accurately. To meet these requirements, an atomic force microscope (AFM) for measuring the 3D edge profiles of tools having nanometer-scale cutting edge radii with high resolution has been developed [7-8]. Although the AFM probe unit is combined with an optical sensor for aligning the measurement probe with the tools edge top to be measured in short time in this system, this time only the AFM probe unit was used. During the measurement time, that was attached onto the ultra precision turning machine to confirm the possibility of profile measurement system.

Protecting Dark Skies in Chile

NASA Astrophysics Data System (ADS)

Smith, R. Chris; Sanhueza, Pedro; Phillips, Mark

2018-01-01

Current projections indicate that Chile will host approximately 70% of the astronomical collecting area on Earth by 2030, augmenting the enormous area of ALMA with that of three next-generation optical telescopes: LSST, GMTO, and E-ELT. These cutting-edge facilities represent billions of dollars of investment in the astronomical facilities hosted in Chile. The Chilean government, Chilean astronomical community, and the international observatories in Chile have recognized that these investments are threatened by light pollution, and have formed a strong collaboration to work at managing the threats. We will provide an update on the work being done in Chile, ranging from training municipalities about new lighting regulations to exploring international recognition of the dark sky sites of Northern Chile.

Ultrasonic Polishing

NASA Technical Reports Server (NTRS)

Gilmore, Randy

1993-01-01

The ultrasonic polishing process makes use of the high-frequency (ultrasonic) vibrations of an abradable tool which automatically conforms to the work piece and an abrasive slurry to finish surfaces and edges on complex, highly detailed, close tolerance cavities in materials from beryllium copper to carbide. Applications range from critical deburring of guidance system components to removing EDM recast layers from aircraft engine components to polishing molds for forming carbide cutting tool inserts or injection molding plastics. A variety of materials including tool steels, carbides, and even ceramics can be successfully processed. Since the abradable tool automatically conforms to the work piece geometry, the ultrasonic finishing method described offers a number of important benefits in finishing components with complex geometries.

Available Tools and Challenges Classifying Cutting-Edge and Historical Astronomical Documents

NASA Astrophysics Data System (ADS)

Lagerstrom, Jill

2015-08-01

The STScI Library assists the Science Policies Division in evaluating and choosing scientific keywords and categories for proposals for the Hubble Space Telescope mission and the upcoming James Webb Space Telescope mission. In addition we are often faced with the question “what is the shape of the astronomical literature?” However, subject classification in astronomy in recent times has not been cultivated. This talk will address the available tools and challenges of classifying cutting-edge as well as historical astronomical documents. In at the process, we will give an overview of current and upcoming practices of subject classification in astronomy.

Diagnosis of edge condition based on force measurement during milling of composites

NASA Astrophysics Data System (ADS)

Felusiak, Agata; Twardowski, Paweł

2018-04-01

The present paper presents comparative results of the forecasting of a cutting tool wear with the application of different methods of diagnostic deduction based on the measurement of cutting force components. The research was carried out during the milling of the Duralcan F3S.10S aluminum-ceramic composite. Prediction of the toolwear was based on one variable, two variables regression Multilayer Perceptron(MLP)and Radial Basis Function(RBF)neural networks. Forecasting the condition of the cutting tool on the basis of cutting forces has yielded very satisfactory results.

Making the Cut: Lattice Kirigami Rules

NASA Astrophysics Data System (ADS)

Castle, Toen; Cho, Yigil; Gong, Xingting; Jung, Euiyeon; Sussman, Daniel M.; Yang, Shu; Kamien, Randall D.

2014-12-01

In this Letter we explore and develop a simple set of rules that apply to cutting, pasting, and folding honeycomb lattices. We consider origami-like structures that are extrinsically flat away from zero-dimensional sources of Gaussian curvature and one-dimensional sources of mean curvature, and our cutting and pasting rules maintain the intrinsic bond lengths on both the lattice and its dual lattice. We find that a small set of rules is allowed providing a framework for exploring and building kirigami—folding, cutting, and pasting the edges of paper.

A facile top-down etching to create a Cu2O jagged polyhedron covered with numerous {110} edges and {111} corners with enhanced photocatalytic activity.

PubMed

Shang, Yang; Sun, Du; Shao, Yiming; Zhang, Dongfeng; Guo, Lin; Yang, Shihe

2012-11-05

Cutting edge: A Cu(2)O jagged polyhedron, with numerous {110} edges and {111} corners, has been developed through a top-down selective oxidative etching process at the expense of the original {111} facet (see figure). The as-prepared nanocrystals exhibited higher photocatalytic activities for the degradation of methylene orange, which may be primarily ascribed to the increased edges and corners. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Edge-facet pumped, multi-aperture, thin-disk laser geometry for very high average power output scaling

DOEpatents

Zapata, Luis E.

2004-12-21

The average power output of a laser is scaled, to first order, by increasing the transverse dimension of the gain medium while increasing the thickness of an index matched light guide proportionately. Strategic facets cut at the edges of the laminated gain medium provide a method by which the pump light introduced through edges of the composite structure is trapped and passes through the gain medium repeatedly. Spontaneous emission escapes the laser volume via these facets. A multi-faceted disk geometry with grooves cut into the thickness of the gain medium is optimized to passively reject spontaneous emission generated within the laser material, which would otherwise be trapped and amplified within the high index composite disk. Such geometry allows the useful size of the laser aperture to be increased, enabling the average laser output power to be scaled.

ScMO(BO3) (M = Ca and Cd): new Sc-based oxyborates featuring interesting edge-sharing sandwich-like chains and UV cut-off edges.

PubMed

Ma, Ruru; Xu, Dongdong; Yang, Yun; Su, Xin; Lei, Binghua; Yang, Zhihua; Pan, Shilie

2017-11-07

Two new isostructural rare-earth oxyborates ScMO(BO 3 ) (M = Ca and Cd) with a three-dimensional (3D) cationic framework and parallel arranged [BO 3 ] triangles have been synthesized by the flux method. In the 3D cationic framework, an interesting sandwich-like basic building unit (BBU) is constructed by two [Ca(1)O 4 ] 6- chains and two [Sc(1)O 4 ] 5- chains. ScMO(BO 3 ) melt incongruently, which shows that title compounds can be grown by the flux method. The UV cut-off edges for ScCaO(BO 3 ) and ScCdO(BO 3 ) are 230 and 249 nm, respectively. In addition, the first-principles calculations are performed to gain further insights into the relationship between the microscopic electronic structures and associated optical properties.

Towards crack-free ablation cutting of thin glass sheets with picosecond pulsed lasers

NASA Astrophysics Data System (ADS)

Sun, Mingying; Eppelt, Urs; Hartmann, Claudia; Schulz, Wolfgang; Zhu, Jianqiang; Lin, Zunqi

2017-08-01

We investigated the morphology and mechanism of laser-induced damage in the ablation cutting of thin glass sheets with picosecond laser. Two kinds of damage morphologies observed on the cross-section of the cut channel, are caused by high-density free-electrons and the temperature accumulation, respectively. Notches and micro-cracks can be observed on the top surface of the sample near the cut edge. The surface micro-cracks were related to high energy free-electrons and also the heat-affected zone. Heat-affected-zone and visible-cracks free conditions of glass cutting were achieved by controlling the repetition rate and spatial overlap of laser pulses.

The Cutting-Edge Challenge

ERIC Educational Resources Information Center

Share, Joani

2005-01-01

In a time of educational budget cuts, the arts seem to take the major brunt of the financial ax. Fine arts programs are often pitted against one another for survival. The music industry and supporting corporations, such as American Express, campaign to have instruments donated or purchased to keep educational programs alive. The visual arts do not…

Microfabricated instrument for tissue biopsy and analysis

DOEpatents

Krulevitch, Peter A.; Lee, Abraham P.; Northrup, M. Allen; Benett, William J.

1999-01-01

A microfabricated biopsy/histology instrument which has several advantages over the conventional procedures, including minimal specimen handling, smooth cutting edges with atomic sharpness capable of slicing very thin specimens (approximately 2 .mu.m or greater), micro-liter volumes of chemicals for treating the specimens, low cost, disposable, fabrication process which renders sterile parts, and ease of use. The cutter is a "cheese-grater" style design comprising a block or substrate of silicon and which uses anisotropic etching of the silicon to form extremely sharp and precise cutting edges. As a specimen is cut, it passes through the silicon cutter and lies flat on a piece of glass which is bonded to the cutter. Microchannels are etched into the glass or silicon substrates for delivering small volumes of chemicals for treating the specimen. After treatment, the specimens can be examined through the glass substrate. For automation purposes, microvalves and micropumps may be incorporated. Also, specimens in parallel may be cut and treated with identical or varied chemicals. The instrument is disposable due to its low cost and thus could replace current expensive microtome and histology equipment.

Experimental evaluation of tool run-out in micro milling

NASA Astrophysics Data System (ADS)

Attanasio, Aldo; Ceretti, Elisabetta

2018-05-01

This paper deals with micro milling cutting process focusing the attention on tool run-out measurement. In fact, among the effects of the scale reduction from macro to micro (i.e., size effects) tool run-out plays an important role. This research is aimed at developing an easy and reliable method to measure tool run-out in micro milling based on experimental tests and an analytical model. From an Industry 4.0 perspective this measuring strategy can be integrated into an adaptive system for controlling cutting forces, with the objective of improving the production quality, the process stability, reducing at the same time the tool wear and the machining costs. The proposed procedure estimates the tool run-out parameters from the tool diameter, the channel width, and the phase angle between the cutting edges. The cutting edge phase measurement is based on the force signal analysis. The developed procedure has been tested on data coming from micro milling experimental tests performed on a Ti6Al4V sample. The results showed that the developed procedure can be successfully used for tool run-out estimation.

Surface Finish and Residual Stresses Induced by Orthogonal Dry Machining of AA7075-T651

PubMed Central

Jomaa, Walid; Songmene, Victor; Bocher, Philippe

2014-01-01

The surface finish was extensively studied in usual machining processes (turning, milling, and drilling). For these processes, the surface finish is strongly influenced by the cutting feed and the tool nose radius. However, a basic understanding of tool/surface finish interaction and residual stress generation has been lacking. This paper aims to investigate the surface finish and residual stresses under the orthogonal cutting since it can provide this information by avoiding the effect of the tool nose radius. The orthogonal machining of AA7075-T651 alloy through a series of cutting experiments was performed under dry conditions. Surface finish was studied using height and amplitude distribution roughness parameters. SEM and EDS were used to analyze surface damage and built-up edge (BUE) formation. An analysis of the surface topography showed that the surface roughness was sensitive to changes in cutting parameters. It was found that the formation of BUE and the interaction between the tool edge and the iron-rich intermetallic particles play a determinant role in controlling the surface finish during dry orthogonal machining of the AA7075-T651 alloy. Hoop stress was predominantly compressive on the surface and tended to be tensile with increased cutting speed. The reverse occurred for the surface axial stress. The smaller the cutting feed, the greater is the effect of cutting speed on both axial and hoop stresses. By controlling the cutting speed and feed, it is possible to generate a benchmark residual stress state and good surface finish using dry machining. PMID:28788534

High speed pulsed laser cutting of LiCoO2 Li-ion battery electrodes

NASA Astrophysics Data System (ADS)

Lutey, Adrian H. A.; Fortunato, Alessandro; Carmignato, Simone; Fiorini, Maurizio

2017-09-01

Laser cutting of Li-ion battery electrodes represents an alternative to mechanical blanking that avoids complications associated with tool wear and allows assembly of different cell geometries with a single device. In this study, laser cutting of LiCoO2 Li-ion battery electrodes is performed at up to 5m /s with a 1064nm wavelength nanosecond pulsed fiber laser with a maximum average power of 500W and a repetition rate of up to 2MHz . Minimum average cutting power for cathode and anode multi-layer films is established for 12 parameter groups with velocities over the range 1 - 5m /s , varying laser pulse fluence and overlap. Within the tested parameter range, minimum energy per unit cut length is found to decrease with increasing repetition rate and velocity. SEM analysis of the resulting cut edges reveals visible clearance widths in the range 20 - 50 μm , with cut quality found to improve with velocity due to a reduction in lateral heat conduction losses. Raman line map spectra reveal changes in the cathode at 60 μm from the cut edge, where bands at 486cm-1 and 595cm-1 , corresponding to the Eg and A1g modes of LiCoO2 , are replaced with a single wide band centered at 544cm-1 , and evidence of carbon black is no longer present. No changes in Raman spectra are observed in the anode. The obtained results suggest that further improvements in cutting efficiency and quality could be achieved by increasing the repetition rate above 2MHz , thereby improving ablation efficiency of the metallic conductor layers. The laser source utilized in the present study nonetheless represents an immediately available solution for repeatability and throughput that are superior to mechanical blanking.

Wedge cutting of mild steel by CO 2 laser and cut-quality assessment in relation to normal cutting

NASA Astrophysics Data System (ADS)

Yilbas, B. S.; Karatas, C.; Uslan, I.; Keles, O.; Usta, Y.; Yilbas, Z.; Ahsan, M.

2008-10-01

In some applications, laser cutting of wedge surfaces cannot be avoided in sheet metal processing and the quality of the end product defines the applicability of the laser-cutting process in such situations. In the present study, CO 2 laser cutting of the wedge surfaces as well as normal surfaces (normal to laser beam axis) is considered and the end product quality is assessed using the international standards for thermal cutting. The cut surfaces are examined by the optical microscopy and geometric features of the cut edges such as out of flatness and dross height are measured from the micrographs. A neural network is introduced to classify the striation patterns of the cut surfaces. It is found that the dross height and out of flatness are influenced significantly by the laser output power, particularly for wedge-cutting situation. Moreover, the cut quality improves at certain value of the laser power intensity.

Method and apparatus for diamond wire cutting of metal structures

DOEpatents

Parsells, Robert; Gettelfinger, Geoff; Perry, Erik; Rule, Keith

2005-04-19

A method and apparatus for diamond wire cutting of metal structures, such as nuclear reactor vessels, is provided. A diamond wire saw having a plurality of diamond beads with beveled or chamfered edges is provided for sawing into the walls of the metal structure. The diamond wire is guided by a plurality of support structures allowing for a multitude of different cuts. The diamond wire is cleaned and cooled by CO.sub.2 during the cutting process to prevent breakage of the wire and provide efficient cutting. Concrete can be provided within the metal structure to enhance cutting efficiency and reduce airborne contaminants. The invention can be remotely controlled to reduce exposure of workers to radioactivity and other hazards.

Coupler for coupling gyrotron whispering gallery mode RF into HE11 waveguide

DOEpatents

Neilson, Jeffrey M

2015-02-24

A cylindrical waveguide with a mode converter transforms a whispering gallery mode from a gyrotron cylindrical waveguide with a helical cut launch edge to a quasi-Gaussian beam suitable for conveyance through a corrugated waveguide. This quasi-Gaussian beam is radiated away from the waveguide using a spiral cut launch edge, which is in close proximity to a first mode converting reflector. The first mode converting reflector is coupled to a second mode converting reflector which provides an output free-space HE11 mode wave suitable for direct coupling into a corrugated waveguide. The radiated beam produced at the output of the second mode converting reflector is substantially circular.

Trajectory Calculator for Finite-Radius Cutter on a Lathe

NASA Technical Reports Server (NTRS)

Savchenkov, Anatoliy; Strekalov, Dmitry; Yu, Nan

2009-01-01

A computer program calculates the two-dimensional trajectory (radial vs. axial position) of a finite-radius-of-curvature cutting tool on a lathe so as to cut a workpiece to a piecewise-continuous, analytically defined surface of revolution. (In the original intended application, the tool is a diamond cutter, and the workpiece is made of a crystalline material and is to be formed into an optical resonator disk.) The program also calculates an optimum cutting speed as F/L, where F is a material-dependent empirical factor and L is the effective instantaneous length of the cutting edge.

Energy Scaling of Nanosecond Gain-Switched Cr2+:ZnSe Lasers

DTIC Science & Technology

2011-01-01

outcoupler or absorption from the lightly-doped active ions. Additionally, the edges of the crystals are cut at the Brewster angle , which raises...experiments we used Brewster cut Cr:ZnSe gain elements with a chromium concentration of 8x1018 cm-3. Under Cr:Tm:Ho:YAG pumping, the first Cr:ZnSe laser...the energy scaling of nanosecond gain-switched Cr:ZnSe lasers is optimization of the gain medium. In this study we used Brewster cut Cr:ZnSe gain

Electrostatic Precipitator

NASA Image and Video Library

2017-06-09

In their Swamp Works laboratory at NASA's Kennedy Space Center, Dr. Carlos Calle and Jay Phillips are testing an electrostatic precipitator using dust that closely approximates the make-up of that on Mars. They upgraded their electrostatic precipitator to fully simulate Martian atmosphere by designing and constructing a dust aerosolization pre-chamber. The agency's Journey to Mars requires cutting-edge technologies to solve the problems explorers will face on the Red Planet. Scientists are developing some of the needed solutions by adapting a device to remove the ever-present dust from valuable elements in the Martian atmosphere. Those commodities include oxygen, water and methane.

Travelers Edge: A Model on the Cutting Edge of Corporate College Access and Success Support

ERIC Educational Resources Information Center

Pell Institute for the Study of Opportunity in Higher Education, 2012

2012-01-01

It is intuitive for businesses and corporations to be worried about the nation's economic competitiveness in the globalized marketplace. To help close this income-based degree attainment gap, models of college access and success programs continue to emerge among the corporate sector. For years, many corporations have established internship and/or…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sisterson, Douglas

Research meteorologist Doug Sisterson discusses climate change and the cutting-edge research taking place at Argonne as well as collaborative research with other institutions, including the University of Chicago.

Temperature measurement of flat glass edge during grinding and effect of wheel and workpiece speeds

NASA Astrophysics Data System (ADS)

Moussa, Tala; Garnier, Bertrand; Peerhossaini, Hassan

2017-06-01

Flat glass temperature at the vicinity of the grinding wheel during grinding can become very high and reach that of the glass transition (typically around 550-600 °C). In such cases, the mechanical strength of glass is greatly affected and the grinding process cannot be carried out properly. Hence, thermal phenomena must be managed by adjusting the machining parameters to avoid overheating. For this purpose, it is very important to be able to measure the glass temperature, especially at the grinding interface. However, measuring the interfacial glass temperature is difficult and none of the existing methods for metal grinding is adequate for glass grinding. This work shows a novel temperature method that uses constantan and copper strips on both sides of the glass plates; thermoelectric contact being provided by the metallic binder of diamond particles in the grinding wheel. This new technique allows the measurement of the glass edge temperature during the wheel displacement around the glass plate. The experimental results show an average glass edge temperature between 300 and 600 °C depending on the value of the machining parameters such as work speed, wheel speed, depth of cut and water coolant flow rate. As this new thermal instrumentation is rather intrusive, glass temperature biases were analysed using a 3D heat transfer model with a moving source. Model computations performed using finite elements show that the temperature biases are less than 70 °C, which is smaller than the standard deviation of the glass edge temperatures measured during grinding.

Surface and cut-edge corrosion behavior of Zn-Mg-Al alloy-coated steel sheets as a function of the alloy coating microstructure

NASA Astrophysics Data System (ADS)

Oh, Min-Suk; Kim, Sang-Heon; Kim, Jong-Sang; Lee, Jae-Won; Shon, Je-Ha; Jin, Young-Sool

2016-01-01

The effects of Mg and Al content on the microstructure and corrosion resistance of hot-dip Zn-Mg-Al alloycoated steel sheets were investigated. Pure Zn and Zn-based alloy coatings containing Mg (0-5 wt%) and Al (0.2-55 wt%) were produced by a hot-dip galvanizing method. Mg and Al addition induced formation of intermetallic microstructures, like primary Zn, Zn/MgZn2 binary eutectic, dendric Zn/Al eutectoid, and Zn/Al/MgZn2/ternary eutectic structures in the coating layer. MgZn2-related structures (Zn/MgZn2, Zn/Al/MgZn2, MgZn2) played an important role in increasing the corrosion resistance of Zn-Mg-Al alloy-coated steel sheets. Zn-3%Mg-2.5%Al coating layer containing a large volume of lamellar-shaped Zn/MgZn2 binary eutectic structures showed the best cut-edge corrosion resistance. The analysis indicated that Mg dissolved from MgZn2 in the early stage of corrosion and migrated to the cathodic region of steel-exposed cut-edge area to form dense and ordered protective corrosion products, leading to prolonged cathodic protection of Zn-Mg-Al alloy-coated steel sheets.

Geometric and computer-aided spline hob modeling

NASA Astrophysics Data System (ADS)

Brailov, I. G.; Myasoedova, T. M.; Panchuk, K. L.; Krysova, I. V.; Rogoza, YU A.

2018-03-01

The paper considers acquiring the spline hob geometric model. The objective of the research is the development of a mathematical model of spline hob for spline shaft machining. The structure of the spline hob is described taking into consideration the motion in parameters of the machine tool system of cutting edge positioning and orientation. Computer-aided study is performed with the use of CAD and on the basis of 3D modeling methods. Vector representation of cutting edge geometry is accepted as the principal method of spline hob mathematical model development. The paper defines the correlations described by parametric vector functions representing helical cutting edges designed for spline shaft machining with consideration for helical movement in two dimensions. An application for acquiring the 3D model of spline hob is developed on the basis of AutoLISP for AutoCAD environment. The application presents the opportunity for the use of the acquired model for milling process imitation. An example of evaluation, analytical representation and computer modeling of the proposed geometrical model is reviewed. In the mentioned example, a calculation of key spline hob parameters assuring the capability of hobbing a spline shaft of standard design is performed. The polygonal and solid spline hob 3D models are acquired by the use of imitational computer modeling.

Minimal processing of iceberg lettuce has no substantial influence on the survival, attachment and internalization of E. coli O157 and Salmonella.

PubMed

Van der Linden, Inge; Avalos Llano, Karina R; Eriksson, Markus; De Vos, Winnok H; Van Damme, Els J M; Uyttendaele, Mieke; Devlieghere, Frank

2016-12-05

The influence of a selection of minimal processing techniques (sanitizing wash prior to packaging, modified atmosphere, storage conditions under light or in the dark) was investigated in relation to the survival of, attachment to and internalization of enteric pathogens in fresh produce. Cut Iceberg lettuce was chosen as a model for fresh produce, Escherichia coli O157:H7 (E. coli O157) and Salmonella enterica were chosen as pathogen models. Care was taken to simulate industrial post-harvest processing. A total of 50±0.1g of fresh-cut Iceberg lettuce was packed in bags under near ambient atmospheric air with approximately 21% O 2 (NAA) conditions or equilibrium modified atmosphere with 3% O 2 (EMAP). Two lettuce pieces inoculated with E. coli O157 BRMSID 188 or Salmonella Typhimurium labeled with green fluorescent protein (GFP) were added to each package. The bags with cut lettuce were stored under either dark or light conditions for 2days at 7°C. The pathogens' capacity to attach to the lettuce surface and cut edge was evaluated 2days after inoculation using conventional plating technique and the internalization of the bacteria was investigated and quantified using confocal microscopy. The effect of a sanitizing wash step (40mg/L NaClO or 40mg/L peracetic acid+1143mg/L lactic acid) of the cut lettuce prior to packaging was evaluated as well. Our results indicate that both pathogens behaved similarly under the investigated conditions. Pathogen growth was not observed, nor was there any substantial influence of the investigated atmospheric conditions or light/dark storage conditions on their attachment/internalization. The pathogens attached to and internalized via cut edges and wounds, from which they were able to penetrate into the parenchyma. Internalization through the stomata into the parenchyma was not observed, although some bacteria were found in the substomatal cavity. Washing the cut edges with sanitizing agents to reduce enteric pathogen numbers was not more effective than a rinse with precooled tap water prior to packaging. Our results confirm that cut surfaces are the main risk for postharvest attachment and internalization of E. coli O157 and Salmonella during minimal processing and that storage and packaging conditions have no important effect. Copyright © 2016 Elsevier B.V. All rights reserved.

Analysis of the application of poly-nanocrystalline diamond tools for ultra precision machining of steel with ultrasonic assistance

NASA Astrophysics Data System (ADS)

Doetz, M.; Dambon, O.; Klocke, F.; Bulla, B.; Schottka, K.; Robertson, D. J.

2017-10-01

Ultra-precision diamond turning enables the manufacturing of parts with mirror-like surfaces and highest form accuracies out of non-ferrous, a few crystalline and plastic materials. Furthermore, an ultrasonic assistance has the ability to push these boundaries and enables the machining of materials like steel, which is not possible in a conventional way due to the excessive tool wear caused by the affinity of carbon to iron. Usually monocrystalline diamonds tools are applied due to their unsurpassed cutting edge properties. New cutting tool material developments have shown that it is possible to produce tools made of nano-polycrystalline diamonds with cutting edges equivalent to monocrystalline diamonds. In nano-polycrystalline diamonds ultra-fine grains of a few tens of nanometers are firmly and directly bonded together creating an unisotropic structure. The properties of this material are described to be isotropic, harder and tougher than those of the monocrystalline diamonds, which are unisotropic. This publication will present machining results from the newest investigations of the process potential of this new polycrystalline cutting material. In order to provide a baseline with which to characterize the cutting material cutting experiments on different conventional machinable materials like Cooper or Aluminum are performed. The results provide information on the roughness and the topography of the surface focusing on the comparison to the results while machining with monocrystalline diamond. Furthermore, the cutting material is tested in machining steel with ultrasonic assistance with a focus on tool life time and surface roughness. An outlook on the machinability of other materials will be given.

Analysis of fabric materials cut using ultraviolet laser ablation

NASA Astrophysics Data System (ADS)

Tsai, Hsin-Yi; Yang, Chih-Chung; Hsiao, Wen-Tse; Huang, Kuo-Cheng; Andrew Yeh, J.

2016-04-01

Laser ablation technology has widely been applied in the clothing industry in recent years. However, the laser mechanism would affect the quality of fabric contours and its components. Hence, this study examined carbonization and oxidation conditions and contour variation in nonwoven, cotton, and composite leather fabrics cut by using an ultraviolet laser at a wavelength of 355 nm. Processing parameters such as laser power, pulse frequency, scanning speed, and number of pulses per spot were adjusted to investigate component variation of the materials and to determine suitable cutting parameters for the fabrics. The experimental results showed that the weights of the component changed substantially by pulse frequency but slightly by laser power, so pulse frequency of 100 kHz and laser power of 14 W were the approximate parameters for three fabrics for the smaller carbonization and a sufficient energy for rapidly cutting, which the pulse duration of laser system was fixed at 300 μs and laser irradiance was 0.98 J/mm2 simultaneously. In addition, the etiolate phenomenon of nonwoven was reduced, and the component weight of cotton and composite leather was closed to the value of knife-cut fabric as the scanning speed increased. The approximate scanning speed for nonwoven and composite leather was 200 mm/s, and one for cotton was 150 mm/s, respectively. The sharper and firmer edge is obtained by laser ablation mechanism in comparison with traditional knife cutting. Experimental results can serve as the reference for laser cutting in the clothing industry, for rapidly providing smoother patterns with lower carbonization and oxidation edge in the fashion industry.

Craterlike structures on the laser cut surface

NASA Astrophysics Data System (ADS)

Shulyatyev, V. B.; Orishich, A. M.

2017-10-01

Analysis of the laser cut surface morphology remain topical. It is related with the fact that the surface roughness is the main index of the cut quality. The present paper deals with the experimental study of the relatively unstudied type of defects on the laser cut surface, dimples, or craters. According to the measurement results, amount of craters per unit of the laser cut surface area rises as the sheet thickness rises. The crater diameter rises together with the sheet thickness and distance from the upper sheet edge. The obtained data permit concluding that the defects like craters are observed predominantly in the case of thick sheets. The results agree with the hypothesis of crater formation as impact structures resulting from the melt drops getting on the cut channel walls upon separation from the cut front by the gas flow.

Optimization of Coolant Technique Conditions for Machining A319 Aluminium Alloy Using Response Surface Method (RSM)

NASA Astrophysics Data System (ADS)

Zainal Ariffin, S.; Razlan, A.; Ali, M. Mohd; Efendee, A. M.; Rahman, M. M.

2018-03-01

Background/Objectives: The paper discusses about the optimum cutting parameters with coolant techniques condition (1.0 mm nozzle orifice, wet and dry) to optimize surface roughness, temperature and tool wear in the machining process based on the selected setting parameters. The selected cutting parameters for this study were the cutting speed, feed rate, depth of cut and coolant techniques condition. Methods/Statistical Analysis Experiments were conducted and investigated based on Design of Experiment (DOE) with Response Surface Method. The research of the aggressive machining process on aluminum alloy (A319) for automotive applications is an effort to understand the machining concept, which widely used in a variety of manufacturing industries especially in the automotive industry. Findings: The results show that the dominant failure mode is the surface roughness, temperature and tool wear when using 1.0 mm nozzle orifice, increases during machining and also can be alternative minimize built up edge of the A319. The exploration for surface roughness, productivity and the optimization of cutting speed in the technical and commercial aspects of the manufacturing processes of A319 are discussed in automotive components industries for further work Applications/Improvements: The research result also beneficial in minimizing the costs incurred and improving productivity of manufacturing firms. According to the mathematical model and equations, generated by CCD based RSM, experiments were performed and cutting coolant condition technique using size nozzle can reduces tool wear, surface roughness and temperature was obtained. Results have been analyzed and optimization has been carried out for selecting cutting parameters, shows that the effectiveness and efficiency of the system can be identified and helps to solve potential problems.

The Role of Dafachronic Acid Signaling in Development and Longevity in Caenorhabditis elegans: Digging Deeper Using Cutting-Edge Analytical Chemistry.

PubMed

Aguilaniu, Hugo; Fabrizio, Paola; Witting, Michael

2016-01-01

Steroid hormones regulate physiological processes in species ranging from plants to humans. A wide range of steroid hormones exist, and their contributions to processes, such as growth, reproduction, development, and aging, is almost always complex. Understanding the biosynthetic pathways that generate steroid hormones and the signaling pathways that mediate their effects is thus of fundamental importance. In this work, we review recent advances in (i) the biological role of steroid hormones in the roundworm Caenorhabditis elegans and (ii) the development of novel methods to facilitate the detection and identification of these molecules. Our current understanding of steroid signaling in this simple organism serves to illustrate the challenges we face moving forward. First, it seems clear that we have not yet identified all of the enzymes responsible for steroid biosynthesis and/or degradation. Second, perturbation of steroid signaling affects a wide range of phenotypes, and subtly different steroid molecules can have distinct effects. Finally, steroid hormone levels are critically important, and minute variations in quantity can profoundly impact a phenotype. Thus, it is imperative that we develop innovative analytical tools and combine them with cutting-edge approaches including comprehensive and highly selective liquid chromatography coupled to mass spectrometry based on new methods such as supercritical fluid chromatography coupled to mass spectrometry (SFC-MS) if we are to obtain a better understanding of the biological functions of steroid signaling.

Effect of Cut Quality on Hybrid Laser Arc Welding of Thick Section Steels

NASA Astrophysics Data System (ADS)

Farrokhi, F.; Nielsen, S. E.; Schmidt, R. H.; Pedersen, S. S.; Kristiansen, M.

From an industrial point of view, in a laser cutting-welding production chain, it is of great importance to know the influence of the attainable laser cut quality on the subsequent hybrid laser arc welding process. Many studies have been carried out in the literature to obtain lower surface roughness values on the laser cut edge. However, in practice, the cost and reliability of the cutting process is crucial and it does not always comply with obtaining the highest surface quality. In this study, a number of experiments on 25 mm steel plates were carried out to evaluate the influence of cut surface quality on the final quality of the subsequent hybrid laser welded joints. The different cut surfaces were obtained by different industrial cutting methods including laser cutting, abrasive water cutting, plasma cutting, and milling. It was found that the mentioned cutting methods could be used as preparation processes for the subsequent hybrid laser arc welding. However, cut quality could determine the choice of process parameters of the following hybrid laser arc welding.

Tubing and cable cutting tool

NASA Technical Reports Server (NTRS)

Mcsmith, D. D.; Richardson, J. I. (Inventor)

1984-01-01

A hand held hydraulic cutting tool was developed which is particularly useful in deactivating ejection seats in military aircraft rescue operations. The tool consists primarily of a hydraulic system composed of a fluid reservoir, a pumping piston, and an actuator piston. Mechanical cutting jaws are attached to the actuator piston rod. The hydraulic system is controlled by a pump handle. As the pump handle is operated the actuator piston rod is forced outward and thus the cutting jaws are forced together. The frame of the device is a flexible metal tubing which permits easy positioning of the tool cutting jaws in remote and normally inaccessible locations. Bifurcated cutting edges ensure removal of a section of the tubing or cable to thereby reduce the possibility of accidental reactivation of the tubing or cable being severed.

Optimizing your vascular practice: how to communicate with referring doctors, increase referrals, and work with cardiologists and interventional radiologists.

PubMed

Jain, Krishna M; Munn, John S; Rummel, Mark C; Johnston, Dan; Longton, Chris; Klemens, Tammy; Cotten, Lisa

2010-12-01

After the fellowship in vascular surgery is completed there is the daunting task of going into practice and succeeding. There are various tools that one can use to succeed in practice and also work closely with other specialists. The key to success is marketing and innovation. Using the two together any vascular surgeon can succeed. Marketing has multiple facets not to be confused with advertising. Total marketing revolves around the surgeon. It involves personal attributes, running of the office, behavior in the hospital, working with other physicians, and using advertising channels. Innovation is required as the art and science of the specialty continues to evolve. Vascular surgeons need to be on the cutting edge of providing latest technology as well as latest methods of delivering care.

Calculation of Water Entry Problem for Free-falling Bodies Using a Developed Cartesian Cut Cell Mesh

NASA Astrophysics Data System (ADS)

Wenhua, Wang; Yanying, Wang

2010-05-01

This paper describes the development of free surface capturing method on Cartesian cut cell mesh to water entry problem for free-falling bodies with body-fluid interaction. The incompressible Euler equations for a variable density fluid system are presented as governing equations and the free surface is treated as a contact discontinuity by using free surface capturing method. In order to be convenient for dealing with the problem with moving body boundary, the Cartesian cut cell technique is adopted for generating the boundary-fitted mesh around body edge by cutting solid regions out of a background Cartesian mesh. Based on this mesh system, governing equations are discretized by finite volume method, and at each cell edge inviscid flux is evaluated by means of Roe's approximate Riemann solver. Furthermore, for unsteady calculation in time domain, a time accurate solution is achieved by a dual time-stepping technique with artificial compressibility method. For the body-fluid interaction, the projection method of momentum equations and exact Riemann solution are applied in the calculation of fluid pressure on the solid boundary. Finally, the method is validated by test case of water entry for free-falling bodies.

Quick-scanning x-ray absorption spectroscopy system with a servo-motor-driven channel-cut monochromator with a temporal resolution of 10 ms.

PubMed

Nonaka, T; Dohmae, K; Araki, T; Hayashi, Y; Hirose, Y; Uruga, T; Yamazaki, H; Mochizuki, T; Tanida, H; Goto, S

2012-08-01

We have developed a quick-scanning x-ray absorption fine structure (QXAFS) system and installed it at the recently constructed synchrotron radiation beamline BL33XU at the SPring-8. Rapid acquisition of high-quality QXAFS data was realized by combining a servo-motor-driven Si channel-cut monochromator with a tapered undulator. Two tandemly aligned monochromators with channel-cut Si(111) and Si(220) crystals covered energy ranges of 4.0-28.2 keV and 6.6-46.0 keV, respectively. The system allows the users to adjust instantly the energy ranges of scans, the starting angles of oscillations, and the frequencies. The channel-cut crystals are cooled with liquid nitrogen to enable them to withstand the high heat load from the undulator radiation. Deformation of the reflecting planes is reduced by clamping each crystal with two cooling blocks. Performance tests at the Cu K-edge demonstrated sufficiently high data quality for x-ray absorption near-edge structure and extended x-ray absorption fine-structure analyses with temporal resolutions of up to 10 and 25 ms, respectively.

Optimized cutting and forming parameters for a robust collar drawing process for hot-rolled complex-phase steels

NASA Astrophysics Data System (ADS)

Kovacs, S.; Beier, T.; Woestmann, S.

2017-09-01

The demands on materials for automotive applications are steadily increasing. For chassis components, the trend is towards thinner and higher strength materials for weight and cost reduction. In view of attainable strengths of up to 1200 MPa for hot rolled materials, certain aspects need to be analysed and evaluated in advance in the development process using these materials. Collars in particular, for example in control arms, have been in focus for part and process design. Issues concerning edge and surface cracks are observed due to improper geometry and process layout. The hole expansion capability of the chosen material grade has direct influence on the achievable collar height. In general, shear cutting reduces the residual formability of blank edges and the hole expansion capability. In this paper, using the example of the complex phase steel CP-W® 800 of thyssenkrupp, it is shown how a suitable geometry of a collar and optimum shear cutting parameters can be chosen.

Modelling of Tool Wear and Residual Stress during Machining of AISI H13 Tool Steel

NASA Astrophysics Data System (ADS)

Outeiro, José C.; Umbrello, Domenico; Pina, José C.; Rizzuti, Stefania

2007-05-01

Residual stresses can enhance or impair the ability of a component to withstand loading conditions in service (fatigue, creep, stress corrosion cracking, etc.), depending on their nature: compressive or tensile, respectively. This poses enormous problems in structural assembly as this affects the structural integrity of the whole part. In addition, tool wear issues are of critical importance in manufacturing since these affect component quality, tool life and machining cost. Therefore, prediction and control of both tool wear and the residual stresses in machining are absolutely necessary. In this work, a two-dimensional Finite Element model using an implicit Lagrangian formulation with an automatic remeshing was applied to simulate the orthogonal cutting process of AISI H13 tool steel. To validate such model the predicted and experimentally measured chip geometry, cutting forces, temperatures, tool wear and residual stresses on the machined affected layers were compared. The proposed FE model allowed us to investigate the influence of tool geometry, cutting regime parameters and tool wear on residual stress distribution in the machined surface and subsurface of AISI H13 tool steel. The obtained results permit to conclude that in order to reduce the magnitude of surface residual stresses, the cutting speed should be increased, the uncut chip thickness (or feed) should be reduced and machining with honed tools having large cutting edge radii produce better results than chamfered tools. Moreover, increasing tool wear increases the magnitude of surface residual stresses.

Design of a surgical instrument for removing bone to provide screw access to a spinal fusion cage.

PubMed

Jabbary Aslani, F; Hukins, D W L; Shepherd, D E T; Parry, J J; Fennell, A J; Lambell, S

2012-01-01

A surgical instrument to aid implantation of a range of lumbar spinal fusion cages has been developed. Once the cage is in position, the entrance to screw holes is partially blocked by the edge of the vertebral body. In order to insert fixation screws to secure the cage between the vertebrae, some part of the blocking edge has to be removed. Rongeurs are currently being used, but they can be time consuming and have the disadvantage that they may remove more bone than is necessary and may cause damage to the fusion cage if not used with care. In addition, access around some of the screw holes may be difficult. The aim of this instrument was to overcome these shortcomings. This paper describes the design of a surgical instrument for cutting edges from vertebral bodies. The development and evaluation of concept designs are presented and discussed. Potential risks were considered and modifications were performed on the selected concept. Functional prototypes were manufactured and tested on sheep lumbar vertebrae. The results showed that the newly designed cutting instrument functions as required and removes the required amount of bone from the vertebral body edge.

Large-scale experimental landscapes reveal distinctive effects of patch shape and connectivity on arthropod communities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orrock, John, L.; Curler, Gregory, R.; Danielson, Brent, J.

2011-09-14

The size, shape, and isolation of habitat patches can affect organism behavior and population dynamics, but little is known about the relative role of shape and connectivity in affecting ecological communities at large spatial scales. Using six sampling sessions from July 2001 until August 2002, we collected 33,685 arthropods throughout seven 12-ha experimental landscapes consisting of clear-cut patches surrounded by a matrix of mature pine forest. Patches were explicitly designed to manipulate connectivity (via habitat corridors) independently of area and edge effects. We found that patch shape, rather than connectivity, affected ground-dwelling arthropod richness and beta diversity (i.e. turnover ofmore » genera among patches). Arthropod communities contained fewer genera and exhibited less turnover in high-edge connected and high-edge unconnected patches relative to low-edge unconnected patches of similar area. Connectivity, rather than patch shape, affected the evenness of ground-dwelling arthropod communities; regardless of patch shape, high-edge connected patches had lower evenness than low- or high-edge unconnected patches. Among the most abundant arthropod orders, increased richness in low-edge unconnected patches was largely due to increased richness of Coleoptera, whereas Hymenoptera played an important role in the lower evenness in connected patches and patterns of turnover. These findings suggest that anthropogenic habitat alteration can have distinct effects on ground-dwelling arthropod communities that arise due to changes in shape and connectivity. Moreover, this work suggests that corridors, which are common conservation tools that change both patch shape and connectivity, can have multiple effects on arthropod communities via different mechanisms, and each effect may alter components of community structure.« less

Condition monitoring of turning process using infrared thermography technique - An experimental approach

NASA Astrophysics Data System (ADS)

Prasad, Balla Srinivasa; Prabha, K. Aruna; Kumar, P. V. S. Ganesh

2017-03-01

In metal cutting machining, major factors that affect the cutting tool life are machine tool vibrations, tool tip/chip temperature and surface roughness along with machining parameters like cutting speed, feed rate, depth of cut, tool geometry, etc., so it becomes important for the manufacturing industry to find the suitable levels of process parameters for obtaining maintaining tool life. Heat generation in cutting was always a main topic to be studied in machining. Recent advancement in signal processing and information technology has resulted in the use of multiple sensors for development of the effective monitoring of tool condition monitoring systems with improved accuracy. From a process improvement point of view, it is definitely more advantageous to proactively monitor quality directly in the process instead of the product, so that the consequences of a defective part can be minimized or even eliminated. In the present work, a real time process monitoring method is explored using multiple sensors. It focuses on the development of a test bed for monitoring the tool condition in turning of AISI 316L steel by using both coated and uncoated carbide inserts. Proposed tool condition monitoring (TCM) is evaluated in the high speed turning using multiple sensors such as Laser Doppler vibrometer and infrared thermography technique. The results indicate the feasibility of using the dominant frequency of the vibration signals for the monitoring of high speed turning operations along with temperatures gradient. A possible correlation is identified in both regular and irregular cutting tool wear. While cutting speed and feed rate proved to be influential parameter on the depicted temperatures and depth of cut to be less influential. Generally, it is observed that lower heat and temperatures are generated when coated inserts are employed. It is found that cutting temperatures are gradually increased as edge wear and deformation developed.

Psychotherapy supervision developments and innovations for the new millennium: contributions from the cutting edge.

PubMed

Watkins, C Edward

2014-01-01

What are some of the most recent, cutting-edge developments and innovations in psychotherapy supervision? And what is their particular significance for supervision now and into its future? In this special supervision issue of the American Journal of Psychotherapy, those questions are considered, and some compelling answers are provided. In what follows, I introduce this special journal issue: (a) define supervision and indicate its purposes; (b) summarize the contents of each innovative paper; and (c) accentuate the significance of each presented development/innovation. The papers contained in this issue boldly speak to supervision's future and provide exciting--and highly profitable--directions to pursue in forever making psychotherapy supervision a far more anchored, accountable, and educational experience.

Coherent structures shed by multiscale cut-in trailing edge serrations on lifting wings

NASA Astrophysics Data System (ADS)

Prigent, S. L.; Buxton, O. R. H.; Bruce, P. J. K.

2017-07-01

This experimental study presents the effect of multiscale cut-in trailing edge serrations on the coherent structures shed into the wake of a lifting wing. Two-probe span-wise hot-wire traverses are performed to study spectra, coherence, and phase shift. In addition, planar particle image velocimetry is used to study the spatio-temporal structure of the vortices shed by the airfoils. Compared with a single tone sinusoidal serration, the multiscale ones reduce the vortex shedding energy as well as the span-wise coherence. Results indicate that the vortex shedding is locked into an arch-shaped cell structure. This structure is weakened by the multiscale patterns, which explains the reduction in both shedding energy and coherence.

Conveying Cutting-Edge Discoveries to Nonscientists: Effective Communication with Media

NASA Astrophysics Data System (ADS)

Gupta, Nikhil; Hamilton, Kathleen; Chamot, Joshua

2013-07-01

The benefits of using information and news media for disseminating cutting-edge scientific discoveries to the public are well known. Taxpayers and lawmakers need to be informed about the implications of public investments, young students' interest can be molded toward science- and technology-based careers, and public awareness of important issues can be raised by effectively using media. However, communication with news media is different from the means commonly used by scientists—journal publications and conference presentations. This article is intended to provide information on three basic aspects of media interactions—why, what, and how to communicate. The increasing importance of this mode of dissemination in this information age cannot be ignored; rather, it can be effectively utilized for educating a wider population base.

Three-Dimensional Printing of Nanomaterial Scaffolds for Complex Tissue Regeneration

PubMed Central

O'Brien, Christopher M.; Holmes, Benjamin; Faucett, Scott

2015-01-01

Three-dimensional (3D) printing has recently expanded in popularity, and become the cutting edge of tissue engineering research. A growing emphasis from clinicians on patient-specific care, coupled with an increasing knowledge of cellular and biomaterial interaction, has led researchers to explore new methods that enable the greatest possible control over the arrangement of cells and bioactive nanomaterials in defined scaffold geometries. In this light, the cutting edge technology of 3D printing also enables researchers to more effectively compose multi-material and cell-laden scaffolds with less effort. In this review, we explore the current state of 3D printing with a focus on printing of nanomaterials and their effect on various complex tissue regeneration applications. PMID:25084122

Single crystal diamond lapping procedure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grayson, R.A.

A facility capable of resharpening quality cutting edges on single crystal diamond cutting tools was needed as the demand in precision machining of special optical surfaces became a common occurrence here at Lawrence Livermore National Laboratory. A specially constructed lapping machine using an air bearing spindle was built to achieve the required edge quality. The basic design for this lap was taken out of a technical report by W.L. Duke and R.T. Lovell of Oak Ridge Y-12 Plant Union Carbide Corp. We have also purchased two commercially built lapping machines recommended to us by Mr. Cory A. Knottenbelt, formerly ofmore » R.C.A. Diamond Lapping Facility, in Indianapolis, Indiana, now doing state-of-the-art polishing and relapping at LLNL facilities.« less

Imaging, cutting, and collecting instrument and method

DOEpatents

Tench, Robert J.; Siekhaus, Wigbert J.; Balooch, Mehdi; Balhorn, Rodney L.; Allen, Michael J.

1995-01-01

Instrumentation and techniques to image small objects, such as but not limited to individual human chromosomes, with nanometer resolution, to cut-off identified parts of such objects, to move around and manipulate such cut-off parts on the substrate on which they are being imaged to predetermined locations on the substrate, and to remove the cut-off parts from the substrate. This is accomplished using an atomic force microscope (AFM) and by modification of the conventional cantilever stylus assembly of an AFM, such that plural cantilevers are used with either sharp-tips or knife-edges thereon. In addition, the invention can be utilized for measuring hardness of materials.

Translating Research Into E/PO That Addresses Real Needs in K-12 Classrooms

NASA Astrophysics Data System (ADS)

van der Veen, Wil E.; Belbruno, E. A.; Roelofsen Moody, T.

2009-01-01

One of the challenges in NASA ROSES E/PO is translating cutting edge research into products for which there is a demonstrated need. Rather than working from the premise that the "research is so cool’ that K-12 students or the public should learn about it, it is key to consult with the target audience to identify what their needs really are. The partnership between NJACE, Innovative Orbital Design, Inc., and Princeton offered a unique opportunity to translate intriguing but theoretical and mathematical research related to low energy orbits into a valuable education product. NJACE worked with educators to identify several needs with an intellectual link to this research: 1) Understanding of Gravity and Newton's Laws, 2) Understanding of Energy and Energy Transformations, 3) Integration of the sciences with math and technology, and 4) Knowledge of NASA's past accomplishments (such as the moon landings). Based on these identified needs, two science units were developed for students in grades 5-12 that integrate astronomy, physics, and the life sciences with math and technology. In addition an engaging public lecture was developed that tells a personal story of the quest for more economic space travel. In the past year, the workshops have been presented on three occasions, reaching over 75 teachers and demand exceeded available space with numerous teachers on waiting lists. The lecture has been presented numerous times at planetariums, museums, amateur astronomy and other clubs. We hope that our partnership will serve as a useful example of how to translate cutting edge research into valuable education products with an identified need. We will provide handouts with links to a website where the products and training can be downloaded in hope that others will help disseminate our product.

Illusory displacement of equiluminous kinetic edges.

PubMed

Ramachandran, V S; Anstis, S M

1990-01-01

A stationary window was cut out of a stationary random-dot pattern. When a field of dots was moved continuously behind the window (a) the window appeared to move in the same direction even though it was stationary, (b) the position of the 'kinetic edges' defining the window was also displaced along the direction of dot motion, and (c) the edges of the window tended to fade on steady fixation even though the dots were still clearly visible. The illusory displacement was enhanced considerably if the kinetic edge was equiluminous and if the 'window' region was seen as 'figure' rather than 'ground'. Since the extraction of kinetic edges probably involves the use of direction-selective cells, the illusion may provide insights into how the visual system uses the output of these cells to localize the kinetic edges.

United Leukodystrophy Foundation

MedlinePlus

... in 1982, is a non-profit, voluntary health organization dedicated to funding cutting-edge research and to providing patients and their families with disease information and medical referrals. The Foundation ...

Emergency Response and Management Activities

EPA Pesticide Factsheets

This quarterly report, highlighting accomplishments over the past several months, showcases EPA’s unique emergency response capabilities through the use of cutting-edge technologies and innovative cleanup strategies.

Cutting thread at flexible endoscopy.

PubMed

Gong, F; Swain, P; Kadirkamanathan, S; Hepworth, C; Laufer, J; Shelton, J; Mills, T

1996-12-01

New thread-cutting techniques were developed for use at flexible endoscopy. A guillotine was designed to follow and cut thread at the endoscope tip. A new method was developed for guiding suture cutters. Efficacy of Nd: YAG laser cutting of threads was studied. Experimental and clinical experience with thread-cutting methods is presented. A 2.4 mm diameter flexible thread-cutting guillotine was constructed featuring two lateral holes with sharp edges through which sutures to be cut are passed. Standard suture cutters were guided by backloading thread through the cutters extracorporeally. A snare cutter was constructed to retrieve objects sewn to tissue. Efficacy and speed of Nd: YAG laser in cutting twelve different threads were studied. The guillotine cut thread faster (p < 0.05) than standard suture cutters. Backloading thread shortened time taken to cut thread (p < 0.001) compared with free-hand cutting. Nd: YAG laser was ineffective in cutting uncolored threads and slower than mechanical cutters. Results of thread cutting in clinical studies using sewing machine (n = 77 cutting episodes in 21 patients), in-vivo experiments (n = 156), and postsurgical cases (n = 15 over 15 years) are presented. New thread-cutting methods are described and their efficacy demonstrated in experimental and clinical studies.

Reducing Coal Dust With Water Jets

NASA Technical Reports Server (NTRS)

Gangal, M. D.; Lewis, E. V.

1985-01-01

Jets also cool and clean cutting equipment. Modular pick-and-bucket miner suffers from disadvantage: Creates large quantities of potentially explosive coal dust. Dust clogs drive chain and other parts and must be removed by hand. Picks and bucket lips become overheated by friction and be resharpened or replaced frequently. Addition of oscillating and rotating water jets to pick-and-bucket machine keeps down dust, cools cutting edges, and flushes machine. Rotating jets wash dust away from drive chain. Oscillating jets cool cutting surfaces. Both types of jet wet airborne coal dust; it precipitates.

The Effect of Cutting Speed in Metallic Glass Grinding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Serbest, Erdinc; Bakkal, Mustafa; Karipcin, Ilker

2011-01-17

In this paper, the effects of the cutting speed in metallic glass grinding were investigated in dry conditions. The results showed that grinding forces decrease as grinding energy increase with the increasing cutting speeds. The present investigations on ground surface and grinding chips morphologies -shows that material removal and surface formation of the BMG are mainly due to the ductile chip deformation and ploughing as well as brittle fracture of some particles from the edges of the tracks. The roughness values obtained with the Cubic Boron Nitride wheels are acceptable for the grinding operation.

High pressure water jet mining machine

DOEpatents

Barker, Clark R.

1981-05-05

A high pressure water jet mining machine for the longwall mining of coal is described. The machine is generally in the shape of a plowshare and is advanced in the direction in which the coal is cut. The machine has mounted thereon a plurality of nozzle modules each containing a high pressure water jet nozzle disposed to oscillate in a particular plane. The nozzle modules are oriented to cut in vertical and horizontal planes on the leading edge of the machine and the coal so cut is cleaved off by the wedge-shaped body.

Co-optimization of lithographic and patterning processes for improved EPE performance

NASA Astrophysics Data System (ADS)

Maslow, Mark J.; Timoshkov, Vadim; Kiers, Ton; Jee, Tae Kwon; de Loijer, Peter; Morikita, Shinya; Demand, Marc; Metz, Andrew W.; Okada, Soichiro; Kumar, Kaushik A.; Biesemans, Serge; Yaegashi, Hidetami; Di Lorenzo, Paolo; Bekaert, Joost P.; Mao, Ming; Beral, Christophe; Larivière, Stephane

2017-03-01

Complimentary lithography is already being used for advanced logic patterns. The tight pitches for 1D Metal layers are expected to be created using spacer based multiple patterning ArF-i exposures and the more complex cut/block patterns are made using EUV exposures. At the same time, control requirements of CDU, pattern shift and pitch-walk are approaching sub-nanometer levels to meet edge placement error (EPE) requirements. Local variability, such as Line Edge Roughness (LER), Local CDU, and Local Placement Error (LPE), are dominant factors in the total Edge Placement error budget. In the lithography process, improving the imaging contrast when printing the core pattern has been shown to improve the local variability. In the etch process, it has been shown that the fusion of atomic level etching and deposition can also improve these local variations. Co-optimization of lithography and etch processing is expected to further improve the performance over individual optimizations alone. To meet the scaling requirements and keep process complexity to a minimum, EUV is increasingly seen as the platform for delivering the exposures for both the grating and the cut/block patterns beyond N7. In this work, we evaluated the overlay and pattern fidelity of an EUV block printed in a negative tone resist on an ArF-i SAQP grating. High-order Overlay modeling and corrections during the exposure can reduce overlay error after development, a significant component of the total EPE. During etch, additional degrees of freedom are available to improve the pattern placement error in single layer processes. Process control of advanced pitch nanoscale-multi-patterning techniques as described above is exceedingly complicated in a high volume manufacturing environment. Incorporating potential patterning optimizations into both design and HVM controls for the lithography process is expected to bring a combined benefit over individual optimizations. In this work we will show the EPE performance improvement for a 32nm pitch SAQP + block patterned Metal 2 layer by cooptimizing the lithography and etch processes. Recommendations for further improvements and alternative processes will be given.

Impact Of Recent Timber Harvests On Autumn Scenic Beauty Of Near-Stand Views

Treesearch

Rebecca J. Ray Barlow; Victor A. Rudis

2004-01-01

Abstract - This study estimated the impact of 10 recent timber cutting regimes on the autumn scenic beauty of shortleaf pine-hardwood forests in the Ouachita Mountains of Arkansas. Scenes were photographed near forest stand edges—views typically observed by sightseeing visitors—from 36 treated areas cut the previous winter and 3 comparable untreated...

Calculating and Mitigating the Risk of a Cut Glove to a Space Walking Astronaut

NASA Technical Reports Server (NTRS)

Castillo, Theresa; Haught, Megan

2013-01-01

One of the high risk operations on the International Space Station (ISS) is conducting a space walk, or an Extra Vehicular Activity (EVA). Threats to the space walking crew include airlock failures, space suit failures, and strikes from micro ]meteoroids and orbital debris (MM/OD). There are risks of becoming untethered from the space station, being pinched between the robotic arm and a piece of equipment, tearing your suit on a sharp edge, and other human errors that can be catastrophic. For decades NASA identified and tried to control sharp edges on external structure and equipment by design; however a new and unexpected source of sharp edges has since become apparent. Until recently, one of the underappreciated environmental risks was damage to EVA gloves during a spacewalk. The ISS has some elements which have been flying in the environment of space for over 14 years. It has and continues to be bombarded with MM/OD strikes that have created small, sharp craters all over the structure, including the dedicated EVA handrails and surrounding structure. These craters are capable of cutting through several layers of the EVA gloves. Starting in 2006, five EVA crewmembers reported cuts in their gloves so large they rendered the gloves unusable and in some cases cut the spacewalk short for the safety of the crew. This new hazard took engineers and managers by surprise. NASA has set out to mitigate this risk to safety and operations by redesigning the spacesuit gloves to be more resilient and designing a clamp to isolate MM/OD strikes on handrails, and is considering the necessity of an additional tool to repair strikes on non ]handrail surfaces (such as a file). This paper will address how the ISS Risk Team quantified an estimate of the MM/OD damage to the ISS, and the resulting likelihood of sustaining a cut glove in order to measure the effectiveness of the solutions being investigated to mitigate this risk to the mission and crew.

Sectioning Coated Specimens Without Edge Rounding

NASA Technical Reports Server (NTRS)

Mckechnie, Timothy N.

1988-01-01

New method devised for preparation of cross sections of coated specimens for scanning electron microscopy or energy-dispersive analysis without rounding edges of coatings. After cutting and polishing, specimen section remains smooth and flat so it can be examined under high magnification out to edge of coating. Sectioned blade first electroplated with hard nickel 0.003 in., then encapsulated in two layers of material: soft conductive material at bottom and 0.25 in. of hard diallyl phthalate at top. Nickel plate provides electrical path from surface of section to conductive material below.

Theoretical study of cut area of reduction of large surfaces of rotation parts on machines with rotary cutters “Extra”

NASA Astrophysics Data System (ADS)

Bondarenko, J. A.; Fedorenko, M. A.; Pogonin, A. A.

2018-03-01

Large parts can be treated without disassembling machines using “Extra”, having technological and design challenges, which differ from the challenges in the processing of these components on the stationary machine. Extension machines are used to restore large parts up to the condition allowing one to use them in a production environment. To achieve the desired accuracy and surface roughness parameters, the surface after rotary grinding becomes recoverable, which greatly increases complexity. In order to improve production efficiency and productivity of the process, the qualitative rotary processing of the machined surface is applied. The rotary cutting process includes a continuous change of the cutting edge surfaces. The kinematic parameters of a rotary cutting define its main features and patterns, the cutting operation of the rotary cutting instrument.

Laser cutting: industrial relevance, process optimization, and laser safety

NASA Astrophysics Data System (ADS)

Haferkamp, Heinz; Goede, Martin; von Busse, Alexander; Thuerk, Oliver

1998-09-01

Compared to other technological relevant laser machining processes, up to now laser cutting is the application most frequently used. With respect to the large amount of possible fields of application and the variety of different materials that can be machined, this technology has reached a stable position within the world market of material processing. Reachable machining quality for laser beam cutting is influenced by various laser and process parameters. Process integrated quality techniques have to be applied to ensure high-quality products and a cost effective use of the laser manufacturing plant. Therefore, rugged and versatile online process monitoring techniques at an affordable price would be desirable. Methods for the characterization of single plant components (e.g. laser source and optical path) have to be substituted by an omnivalent control system, capable of process data acquisition and analysis as well as the automatic adaptation of machining and laser parameters to changes in process and ambient conditions. At the Laser Zentrum Hannover eV, locally highly resolved thermographic measurements of the temperature distribution within the processing zone using cost effective measuring devices are performed. Characteristic values for cutting quality and plunge control as well as for the optimization of the surface roughness at the cutting edges can be deducted from the spatial distribution of the temperature field and the measured temperature gradients. Main influencing parameters on the temperature characteristic within the cutting zone are the laser beam intensity and pulse duration in pulse operation mode. For continuous operation mode, the temperature distribution is mainly determined by the laser output power related to the cutting velocity. With higher cutting velocities temperatures at the cutting front increase, reaching their maximum at the optimum cutting velocity. Here absorption of the incident laser radiation is drastically increased due to the angle between the normal of the cutting front and the laser beam axis. Beneath process optimization and control further work is focused on the characterization of particulate and gaseous laser generated air contaminants and adequate safety precautions like exhaust and filter systems.

[Is there life beyond SPSS? Discover R].

PubMed

Elosua Oliden, Paula

2009-11-01

R is a GNU statistical and programming environment with very high graphical capabilities. It is very powerful for research purposes, but it is also an exceptional tool for teaching. R is composed of more than 1400 packages that allow using it for simple statistics and applying the most complex and most recent formal models. Using graphical interfaces like the Rcommander package, permits working in user-friendly environments which are similar to the graphical environment used by SPSS. This last characteristic allows non-statisticians to overcome the obstacle of accessibility, and it makes R the best tool for teaching. Is there anything better? Open, free, affordable, accessible and always on the cutting edge.

Education and Training to Address Specific Needs During the Career Progression of Surgeons.

PubMed

Sachdeva, Ajit K; Blair, Patrice Gabler; Lupi, Linda K

2016-02-01

Surgeons have specific education and training needs as they enter practice, progress through the core period of active practice, and then as they wind down their clinical work before retirement. These transitions and the career progression process, combined with the dynamic health care environment, present specific opportunities for innovative education and training based on practice-based learning and improvement, and continuous professional development methods. Cutting-edge technologies, blended models, simulation, mentoring, preceptoring, and integrated approaches can play critical roles in supporting surgeons as they provide the best surgical care throughout various phases of their careers. Copyright © 2016 Elsevier Inc. All rights reserved.

Deposition of InP-ON-Si Substrates for Monolithic Integration of Advanced Electronics

DTIC Science & Technology

1991-04-19

efficiency, 3 low-cost solar cells , optoelectronic IC’s and GaAs IC’s on large-area Si substrates. Although much work has been done, the performance of the...1. Mesa Diode Fabrication A small piece was cut from the edge of the InP/InP solar cell ---;fr .12-1) I back contact was protected by photoresist. On...1~~~~ A,,).’,**** LLS - .* .’ ~*Ii* En - in - C *- -**0:; iU.)~ ILI Y a.E - CU CU tnJn ~c~C"+ m 00 -~4 CD J - -4i - - Ln cI- C2- El4 wi -r Lf

[Progress in industrial bioprocess engineering in China].

PubMed

Zhuang, Yingping; Chen, Hongzhang; Xia, Jianye; Tang, Wenjun; Zhao, Zhimin

2015-06-01

The advances of industrial biotechnology highly depend on the development of industrial bioprocess researches. In China, we are facing several challenges because of a huge national industrial fermentation capacity. The industrial bioprocess development experienced several main stages. This work mainly reviews the development of the industrial bioprocess in China during the past 30 or 40 years: including the early stage kinetics model study derived from classical chemical engineering, researching method based on control theory, multiple-parameter analysis techniques of on-line measuring instruments and techniques, and multi-scale analysis theory, and also solid state fermentation techniques and fermenters. In addition, the cutting edge of bioprocess engineering was also addressed.

Computational Design of Materials: Planetary Entry to Electric Aircraft and Beyond

NASA Technical Reports Server (NTRS)

Thompson, Alexander; Lawson, John W.

2014-01-01

NASA's projects and missions push the bounds of what is possible. To support the agency's work, materials development must stay on the cutting edge in order to keep pace. Today, researchers at NASA Ames Research Center perform multiscale modeling to aid the development of new materials and provide insight into existing ones. Multiscale modeling enables researchers to determine micro- and macroscale properties by connecting computational methods ranging from the atomic level (density functional theory, molecular dynamics) to the macroscale (finite element method). The output of one level is passed on as input to the next level, creating a powerful predictive model.

Control of the pattern of perithecium development in Sordaria fimicola on agar medium.

PubMed

Pollock, R T

1975-06-01

In a Sordaria fimicola (Rob.) Ces. and de Not. colony grown on agar medium in a petri plate, perithecia developed in a narrow band around the plate edge after the colony margin reached the edge. Physical wounding of the colony carried out shortly before or during the time perithecia were developing around the plate edge stimulated perithecium development in the wound area. Diffusion barriers were created by cutting small trenches in the agar parallel to the plate edge. The trenches were made at several different positions between the plate center and edge using cultures of several different ages, and the resultant distribution of perithecia along the trench edges suggested that the colony center and periphery produce diffusible inhibitors of perithecium development. These inhibitors may be responsible, in part, for the observed pattern of perithecium development in the colony.

Coupling of lithium niobate disk resonators to integrated waveguides

NASA Astrophysics Data System (ADS)

Berneschi, S.; Cosi, F.; Nunzi Conti, G.; Pelli, S.; Soria, S.; Righini, G. C.; Dispenza, M.; Secchi, A.

2011-01-01

Whispering gallery mode (WGM) disk resonators fabricated in single crystals can have high Q factors within their transparency bandwidth and may have application both in fundamental and applied optics. Lithium niobate (LN) resonators thanks to their electro-optical properties may be used in particular as tunable filters, modulators, and delay lines. A critical step toward the actual application of these devices is the implementation of a robust and efficient coupling system. High index prisms are typically used for this purpose. In this work we demonstrate coupling to high-Q WGM LN disks from an integrated optical LN waveguide. The waveguides are made by proton exchange in X-cut LN. The disks with diameters of about 5 mm and thickness of 1 mm are made from commercial Z-cut LN wafers by core drilling a cylinder and thereafter polishing the edges into a spheroidal profile. Both resonance linewidth and cavity photon lifetime measurements were performed to calculate the Q factor of the resonator, which is in excess of 108.

Experimental Analysis of the Influence of Drill Point Angle and Wear on the Drilling of Woven CFRPs

PubMed Central

Feito, Norberto; Díaz-Álvarez, José; Díaz-Álvarez, Antonio; Cantero, José Luis; Miguélez, María Henar

2014-01-01

This paper focuses on the effect of the drill geometry on the drilling of woven Carbon Fiber Reinforced Polymer composite (CFRPs). Although different geometrical effects can be considered in drilling CFRPs, the present work focuses on the influence of point angle and wear because they are the important factors influencing hole quality and machining forces. Surface quality was evaluated in terms of delamination and superficial defects. Three different point angles were tested representative of the geometries commonly used in the industry. Two wear modes were considered, being representative of the wear patterns commonly observed when drilling CFRPs: flank wear and honed cutting edge. It was found that the crossed influence of the point angle and wear were significant to the thrust force. Delamination at the hole entry and exit showed opposite trends with the change of geometry. Also, cutting parameters were checked showing the feed’s dominant influence on surface damage. PMID:28788675

The fracture properties and mechanical design of human fingernails.

PubMed

Farren, L; Shayler, S; Ennos, A R

2004-02-01

Fingernails are a characteristic feature of primates, and are composed of three layers of the fibrous composite keratin. This study examined the structure and fracture properties of human fingernails to determine how they resist bending forces while preventing fractures running longitudinally into the nail bed. Nail clippings were first torn manually to examine the preferred crack direction. Next, scissor cutting tests were carried out to compare the fracture toughness of central and outer areas in both the transverse and longitudinal direction. The fracture toughness of each of the three isolated layers was also measured in this way to determine their relative contributions to the toughness. Finally, the structure was examined by carrying out scanning electron microscopy of free fracture surfaces and polarized light microscopy of nail sections. When nails were torn, cracks were always diverted transversely, parallel to the free edge of the nail. Cutting tests showed that this occurred because the energy to cut nails transversely, at approximately 3 kJ m(-2), was about half that needed (approx. 6 kJ m(-2)) to cut them longitudinally. This anisotropy was imparted by the thick intermediate layer, which comprises long, narrow cells that are oriented transversely; the energy needed to cut this layer transversely was only a quarter of that needed to cut it longitudinally. In contrast the tile-like cells in the thinner dorsal and ventral layers showed isotropic behaviour. They probably act to increase the nail's bending strength, and as they wrap around the edge of the nail, they also help prevent cracks from forming. These results cast light on the mechanical behaviour and care of fingernails.

European road lighting technologies

DOT National Transportation Integrated Search

2001-09-01

The objective of this scanning tour was to gather information from European transportation ministries and lighting professionals regarding cutting-edge research and technologies in highway and roadway lighting systems, including tunnel illumination, ...

Process For Cutting Polymers Electrolyte Multi-Layer Batteries And Batteries Obtained Thereby

DOEpatents

Gauthier, Michel; Lessard, Ginette; Dussault, Gaston; Rouillard, Roger; Simoneau, Martin; Miller, Alan Paul

2003-09-09

A stacking of battery laminate is prepared, each battery consisting of anode, polymer electrolyte, cathode films and possibly an insulating film, under conditions suitable to constitute a rigid monoblock assembly, in which the films are unitary with one another. The assembly obtained is thereafter cut in predetermined shape by using a mechanical device without macroscopic deformation of the films constituting the assembly and without inducing permanent short circuits. The battery which is obtained after cutting includes at least one end which appears as a uniform cut, the various films constituting the assembly having undergone no macroscopic deformation, the edges of the films of the anode including an electronically insulating passivation film.

Effects of blade-vane ratio and rotor-stator spacing of fan noise with forward velocity

NASA Astrophysics Data System (ADS)

Woodward, R. P.; Glaser, F. W.

1981-08-01

A research fan stage was acoustically tested in an anechoic wind tunnel with a 41 m/sec tunnel flow. Two stator vane numbers giving cut-on and cut-off conditions were tested at three rotor-stator spacings ranging from about 0.5 to 2.0 rotor chords. These two stators were designed for similar aerodynamic performance. Hot film anemometer turbulence measurements were made at the leading edge of the stator for each spacing. The cut-off criterion strongly controlled the fundamental tone level at all spacings. The trends with spacing of the wake defect upwash component at the stator tip showed good agreement with the corresponding cut-on acoustic tone levels.

Imaging, cutting, and collecting instrument and method

DOEpatents

Tench, R.J.; Siekhaus, W.J.; Balooch, M.; Balhorn, R.L.; Allen, M.J.

1995-10-31

Instrumentation and techniques are described to image small objects, such as but not limited to individual human chromosomes, with nanometer resolution. This instrument and method are also used to cut-off identified parts of objects, to move around and manipulate the cut-off parts on the substrate on which they are being imaged to predetermined locations on the substrate, and to remove the cut-off parts from the substrate. This is accomplished using an atomic force microscope (AFM) and by modification of the conventional cantilever stylus assembly of an AFM. The plural cantilevers are used with either sharp-tips or knife-edges. In addition, the invention can be utilized for measuring the hardness of materials. 10 figs.

Gyrotron whispering gallery mode coupler with a mode conversion reflector for exciting a circular symmetric uniform phase RF beam in a corrugated waveguide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neilson, Jeffrey M.

A cylindrical waveguide with a mode converter transforms a whispering gallery mode from a gyrotron cylindrical waveguide with a helical cut launch edge to a quasi-Gaussian beam suitable for conveyance through a corrugated waveguide. This quasi-Gaussian beam is radiated away from the waveguide using a spiral cut launch edge, which is in close proximity to a first mode converting reflector. The first mode converting reflector is coupled to a second mode converting reflector which provides an output free-space HE11 mode wave suitable for direct coupling into a corrugated waveguide. The radiated beam produced at the output of the second modemore » converting reflector is substantially circular.« less

International Space Station (ISS)

NASA Image and Video Library

2001-02-01

The Payload Operations Center (POC) is the science command post for the International Space Station (ISS). Located at NASA's Marshall Space Flight Center in Huntsville, Alabama, it is the focal point for American and international science activities aboard the ISS. The POC's unique capabilities allow science experts and researchers around the world to perform cutting-edge science in the unique microgravity environment of space. The POC is staffed around the clock by shifts of payload flight controllers. At any given time, 8 to 10 flight controllers are on consoles operating, plarning for, and controlling various systems and payloads. This photograph shows the Timeline Change Officer (TCO) at a work station. The TCO maintains the daily schedule of science activities and work assignments, and works with planners at Mission Control at Johnson Space Center in Houston, Texas, to ensure payload activities are accommodated in overall ISS plans and schedules.

Frizzled to finance: one PhD’s path from a Drosophila lab to Wall Street

PubMed Central

Taylor, Job

2016-01-01

An equity research analyst’s job is to determine whether the price of a stock is likely to go up or down. For science-based businesses, particularly biotechnology companies, a PhD in the life sciences can be very helpful in making this determination. I transitioned from a postdoc position to working in equity research. Here I present information on how I made the transition, an overview of the day-to-day activities of an analyst, and thoughts on how to prepare to look for a job in finance. There are significant positives to working on Wall Street, including exposure to cutting-edge clinical/translational research, access to some of the best scientists in the world, a dynamic work environment, and compensation that generally exceeds academic salaries. This comes at the cost of some independence and the satisfaction of being able to call oneself a scientist. PMID:27235096

Open ended tubing cutters

NASA Technical Reports Server (NTRS)

Girala, A. S. (Inventor)

1981-01-01

A self clamping cutting tool which includes a handle attached to a C-shaped housing is described. Rotatably mounted within the housing is a C-shaped tool body carrying a set of clamping rolls, two support rolls, and an edged cutting roll (64). The support rolls are disposed to one side of the axis of a pipe and the cutting roll is disposed to the other side of a pipe axis so that these rolls contact a pipe at three circumferential points. Cutter advancing apparatus advance the cutting roll toward the support rollers. The support rolls and cutting roll are rotatable independently of the C-shaped housing. A one way ratchet mechanism disposed between the C-shaped housing and the C-shaped tool body permits operation by movement in one rotational direction about the pipe axis.

LDRD Highlights at the National Laboratories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alayat, R. A.

2016-10-10

To meet the nation’s critical challenges, the Department of Energy (DOE) national laboratories have always pushed the boundaries of science, technology, and engineering. The Atomic Energy Act of 1954 provided the basis for these laboratories to engage in the cutting edge of science and technology and respond to technological surprises, while retaining the best scientific and technological minds. To help re-energize this commitment, in 1991 the U.S. Congress authorized the national laboratories to devote a relatively small percentage of their budget to creative and innovative work that serves to maintain their vitality in disciplines relevant to DOE missions. Since then,more » this effort has been formally called the Laboratory Directed Research and Development (LDRD) Program. LDRD has been an essential mechanism to enable the laboratories to address DOE’s current and future missions with leading-edge research proposed independently by laboratory technical staff, evaluated through expert peer-review committees, and funded by the individual laboratories consistent with the authorizing legislation and the DOE LDRD Order 413.2C.« less

Velcro mechanics in wood

Treesearch

David Kretschmann

2003-12-01

The remarkable deformability of wood in a moist environment resembles that of ductile metals. A combination of traditional mechanical tests and cutting-edge diffraction experiments reveal the molecular mechanism that determines such behaviour.

Optimizing Robinson Operator with Ant Colony Optimization As a Digital Image Edge Detection Method

NASA Astrophysics Data System (ADS)

Yanti Nasution, Tarida; Zarlis, Muhammad; K. M Nasution, Mahyuddin

2017-12-01

Edge detection serves to identify the boundaries of an object against a background of mutual overlap. One of the classic method for edge detection is operator Robinson. Operator Robinson produces a thin, not assertive and grey line edge. To overcome these deficiencies, the proposed improvements to edge detection method with the approach graph with Ant Colony Optimization algorithm. The repairs may be performed are thicken the edge and connect the edges cut off. Edge detection research aims to do optimization of operator Robinson with Ant Colony Optimization then compare the output and generated the inferred extent of Ant Colony Optimization can improve result of edge detection that has not been optimized and improve the accuracy of the results of Robinson edge detection. The parameters used in performance measurement of edge detection are morphology of the resulting edge line, MSE and PSNR. The result showed that Robinson and Ant Colony Optimization method produces images with a more assertive and thick edge. Ant Colony Optimization method is able to be used as a method for optimizing operator Robinson by improving the image result of Robinson detection average 16.77 % than classic Robinson result.

Advanced Turbine Engine Seal Test

DTIC Science & Technology

1976-07-01

Transpiration- Cooled Shroud Segments. 67. ATEST Shroud Rub Pin Heights and Mid-Chord Runout . 68. Locations of Nine-Point Runout Check on Shroud Surface...69. ATEST Shroud Leading Edge Runout . 70. ATEST Shroud Trailing Edge Runout . 71. ATEST Shroud Support Posttest Runout . 72. ATEST Shroud Flow Zones...at General Electric on many prior engines with good success. It Involves the use of a grinding wheel in conjunction with a cutting fluid which is

Exfoliation syndrome: assembling the puzzle pieces.

PubMed

Pasquale, Louis R; Borrás, Terete; Fingert, John H; Wiggs, Janey L; Ritch, Robert

2016-09-01

To summarize various topics and the cutting edge approaches to refine XFS pathogenesis that were discussed at the 21st annual Glaucoma Foundation Think Tank meeting in New York City, Sept. 19-20, 2014. The highlights of three categories of talks on cutting edge research in the field were summarized. Exfoliation syndrome (XFS) is a systemic disorder with a substantial ocular burden, including high rates of cataract, cataract surgery complications, glaucoma and retinal vein occlusion. New information about XFS is akin to puzzle pieces that do not quite join together to reveal a clear picture regarding how exfoliation material (XFM) forms. Meeting participants concluded that it is unclear how the mild homocysteinemia seen in XFS might contribute to the disarrayed extracellular aggregates characteristic of this syndrome. Lysyl oxidase-like 1 (LOXL1) variants are unequivocally genetic risk factors for XFS but exactly how these variants contribute to the assembly of exfoliation material (XFM) remains unclear. Variants in a new genomic region, CACNA1A associated with XFS, may alter calcium concentrations at the cell surface and facilitate XFM formation but much more work is needed before we can place this new finding in proper context. It is hoped that various animal model and ex vivo systems will emerge that will allow for proper assembly of the puzzle pieces into a coherent picture of XFS pathogenesis. A clear understanding of XFS pathogenesis may lead to 'upstream solutions' to reduce the ocular morbidity produced by XFS. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

A high-resolution optical imaging system for obtaining the serial transverse section images of biologic tissue

NASA Astrophysics Data System (ADS)

Wu, Li; Zhang, Bin; Wu, Ping; Liu, Qian; Gong, Hui

2007-05-01

A high-resolution optical imaging system was designed and developed to obtain the serial transverse section images of the biologic tissue, such as the mouse brain, in which new knife-edge imaging technology, high-speed and high-sensitive line-scan CCD and linear air bearing stages were adopted and incorporated with an OLYMPUS microscope. The section images on the tip of the knife-edge were synchronously captured by the reflection imaging in the microscope while cutting the biologic tissue. The biologic tissue can be sectioned at interval of 250 nm with the same resolution of the transverse section images obtained in x and y plane. And the cutting job can be automatically finished based on the control program wrote specially in advance, so we save the mass labor of the registration of the vast images data. In addition, by using this system a larger sample can be cut than conventional ultramicrotome so as to avoid the loss of the tissue structure information because of splitting the tissue sample to meet the size request of the ultramicrotome.

Novel Synthesis of Slightly Fluorinated Graphene Quantum Dots with Luminescent and Paramagnetic Properties through Thermal Cutting of Fluorinated Graphene

PubMed Central

Feng, Qian; Xiao, Wenqing; Zheng, Yongping; Lin, Yuda; Li, Jiaxin; Ye, Qingying; Huang, Zhigao

2018-01-01

A novel approach has been developed to synthesize slightly fluorinated graphene quantum dots (GQDs-F) through thermal cutting of highly fluorinated graphene. The fluorinated graphene with substantial structure defects is fragile and is readily attacked. The direct evaporation of abundant CFn (n = 2, 3) groups near structure defects lead to the loss of adjacent skelton C atoms, and the fluorinated graphene can be thermally cut into GQDs-F with a relatively uniform nanosize in pyrolysis at 810 K. The GQDs-F with a low F/C atomic ratio of ca. 0.03 exhibit excitation wavelength-dependent properties with multicolor photoluminescence (PL) from blue to green. At the same time, F adatoms that are most likely located at the edges of GQDs-F have a high efficiency of introducing paramagnetic centres, and GQDs-F show a strong paramagnetism because of sp3-type defects and magnetic zigzag edges. The graphene quantum dots with such multimodal capabilities should have great applied value in material science. PMID:29316730

Advances in Biological Science.

ERIC Educational Resources Information Center

Oppenheimer, Steven B.; And Others

1988-01-01

Reviews major developments in areas that are at the cutting edge of biological research. Areas include: human anti-cancer gene, recombinant DNA techniques for the detection of Huntington disease carriers, and marine biology. (CW)

21 CFR 882.5900 - Preformed craniosynostosis strip.

Code of Federal Regulations, 2010 CFR

2010-04-01

... bone edges of craniectomy sites (sites where the skull has been cut) to prevent the bone from regrowing in patients whose skull sutures are abnormally fused together. (b) Classification. Class II...

Female high school biology students' biofilm-focused learning: The contributions of three instructional strategies to patterns in understanding and motivation

NASA Astrophysics Data System (ADS)

Ales, Jo Dale Hill

2000-12-01

This exploratory study examined three instructional strategies used with female high school biology students. The relative contributions of the strategies to student understanding of microbiology and motivation in science were analyzed. The science education community targeted underachievement in science by implementing changes in content and practices (NRC, 1996). Research suggested that teachers facilitate learnirig environments based on human constructivism (Mintzes, Wandersee, & Novak, 1997) that is rooted in meaningful learning theory (Ausubel, Novak & Hanesian, 1978). Teachers were advised to use both visual and verbal instructional strategies (Paivio, 1983) and encourage students to construct understandings by connecting new experiences to prior knowledge. The American Society for Microbiology supports the study of microorganisms because of their prominence in the biosphere (ASK 1997). In this study, two participating teachers taught selected microbiology concepts while focused on the cutting edge science of biofilms. Biology students accessed digitized biofilm images on an ASM web page and adapted them into products, communicated with biofilm researchers, and adapted a professional-quality instructional video for cross-age teaching. The study revealed improvements in understanding as evidenced on a written test; however, differences in learnirig outcomes were not significant. Other data, including student journal reflections, observations of student interactions, and student clinical interviews indicate that students were engaged in cutting edge science and adapted biofilm images in ways that increased understanding of microbiology (with respect to both science content and as a way of knowing) and motivation. An ASM CD-ROM of the images did not effectively enhance learning and this study provides insights into what could make it more successful. It also identifies why, in most cases, students' E-mail communication with biofilm researchers was unsuccessful. The positive experiences of successful students indicate that teacher management could maximize the benefits of experiencing cutting edge science this way. Cutting edge science can be used to make science more relevant to students, enhance science learning, and insure a more scientifically literate society. Cross-age teachers effectively adapted an instructional video, communicated science, and increased their understanding of selected microbiology concepts and self-confidence. They also increased or maintained their motivation to study science.

Femtosecond laser-assisted cataract surgery in Alport syndrome with anterior lenticonus.

PubMed

Ecsedy, Mónika; Súndor, Gúbor L; Takúcs, Úgnes I; Krúnitz, Kinga; Kiss, Zoltún; Kolev, Krasimir; Nagy, Zoltún Z

2015-01-01

To report the surgical treatment of 3 eyes of 2 patients with bilateral anterior lenticonus due to Alport syndrome using femtosecond laser-assisted cataract surgery (FLACS). Two patients with Alport syndrome presented to our department due to anterior lenticonus in both eyes. We performed FLACS with posterior chamber lens implantation in both eyes of one patient and in one eye of the other patient. Anterior segment morphologic changes were visualized with a Scheimpflug camera, and anterior segment optical coherence tomography preoperatively and 3 months after surgery. Ultrastructure of the cut capsule edges was observed with scanning electron microscopy and compared to the edge of femtosecond laser capsulotomy performed on an otherwise healthy patient with cataract (control). The intraocular lens (IOL) postoperative positioning parameters met the international requirements of aspherical and wavefront customized IOLs (tilt <10 degree, decentration <800 µm). Scanning electron microscopy revealed the same characteristics of the cut capsule edges in the Alport and in the control eyes. Femtosecond laser cataract surgery can be a safe and successful method for optical rehabilitation of anterior lenticonus in patients with Alport syndrome.

Tool holder for preparation and inspection of a radiused edge cutting tool

DOEpatents

Asmanes, Charles

1979-01-01

A tool holding fixture is provided for removably holding a radiused edge cutting tool in a tool edge lapping apparatus. The fixture allows the operator to preset the lapping radius and angle before the tool holder is placed in the fixture and the holder may be removed from the lapping apparatus to inspect the tool and simply replaced in the fixture to continue lapping in accordance with a precise alignment without realignment of the tool relative to the lap. The tool holder includes a pair of self aligning bearings in the form of precision formed steel balls connected together by a rigid shaft. The tool is held by an arm extending from the shaft and the balls set in fixed position bearing cups and the holder is oscillated back and forth about a fixed axis of rotation to lap the tool radius by means of a reversibly driven belt-pulley arrangement coupled to the shaft between the bearings. To temporarily remove the holder, the drive belt is slipped over the rearward end of the holder and the holder is lifted out of the bearing cups.

The effect of cutting conditions on power inputs when machining

NASA Astrophysics Data System (ADS)

Petrushin, S. I.; Gruby, S. V.; Nosirsoda, Sh C.

2016-08-01

Any technological process involving modification of material properties or product form necessitates consumption of a certain power amount. When developing new technologies one should take into account the benefits of their implementation vs. arising power inputs. It is revealed that procedures of edge cutting machining are the most energy-efficient amongst the present day forming procedures such as physical and technical methods including electrochemical, electroerosion, ultrasound, and laser processing, rapid prototyping technologies etc, such as physical and technical methods including electrochemical, electroerosion, ultrasound, and laser processing, rapid prototyping technologies etc. An expanded formula for calculation of power inputs is deduced, which takes into consideration the mode of cutting together with the tip radius, the form of the replaceable multifaceted insert and its wear. Having taken as an example cutting of graphite iron by the assembled cutting tools with replaceable multifaceted inserts the authors point at better power efficiency of high feeding cutting in comparison with high-speed cutting.

Chip formation and surface integrity in high-speed machining of hardened steel

NASA Astrophysics Data System (ADS)

Kishawy, Hossam Eldeen A.

Increasing demands for high production rates as well as cost reduction have emphasized the potential for the industrial application of hard turning technology during the past few years. Machining instead of grinding hardened steel components reduces the machining sequence, the machining time, and the specific cutting energy. Hard turning Is characterized by the generation of high temperatures, the formation of saw toothed chips, and the high ratio of thrust to tangential cutting force components. Although a large volume of literature exists on hard turning, the change in machined surface physical properties represents a major challenge. Thus, a better understanding of the cutting mechanism in hard turning is still required. In particular, the chip formation process and the surface integrity of the machined surface are important issues which require further research. In this thesis, a mechanistic model for saw toothed chip formation is presented. This model is based on the concept of crack initiation on the free surface of the workpiece. The model presented explains the mechanism of chip formation. In addition, experimental investigation is conducted in order to study the chip morphology. The effect of process parameters, including edge preparation and tool wear on the chip morphology, is studied using Scanning Electron Microscopy (SEM). The dynamics of chip formation are also investigated. The surface integrity of the machined parts is also investigated. This investigation focusses on residual stresses as well as surface and sub-surface deformation. A three dimensional thermo-elasto-plastic finite element model is developed to predict the machining residual stresses. The effect of flank wear is introduced during the analysis. Although residual stresses have complicated origins and are introduced by many factors, in this model only the thermal and mechanical factors are considered. The finite element analysis demonstrates the significant effect of the heat generated during cutting on the residual stresses. The machined specimens are also examined using x-ray diffraction technique to clarify the effect of different speeds, feeds and depths of cut as well as different edge preparations on the residual stress distribution beneath the machined surface. A reasonable agreement between the predicted and measured residual stress is obtained. The results obtained demonstrate the possibility of eliminating the existence of high tensile residual stresses in the workpiece surface by selecting the proper cutting conditions. The machined surfaces are examined using SEM to study the effect of different process parameters and edge preparations on the quality of the machined surface. The phenomenon of material side flow is investigated to clarify the mechanism of this phenomenon. The effect of process parameters and edge preparations on sub-surface deformation is also investigated.

Small Craft Transportability Design and Certification Process Guidance. Revision B

DTIC Science & Technology

2010-11-08

49CFR393.104, wherever a tie-down strap is subject to abrasion or cutting, it should be provided with edge protection capable of resisting abrasion , cutting...commercial round connector shown in Figure 8. Tactical vehicles (e.g., MTVR, High Mobility Multi-Wheeled Vehicle (HMMWV), or Mine Resistant Ambush...a heavy-duty construction, using corrosion- and rot- resistant (or coated) materials and components. Trailer components are likely to be submerged

Herbivorous insect response to group selection cutting in a southeastern bottomland hardwood forest

Treesearch

Michael D. Ulyshen; James L. Hanula; Scott Horn; John C. Kilgo; Christopher E. Moorman

2005-01-01

Malaise and pitfall traps were used to sample herbivorous insects in canopy gaps created by group-selection cutting in a bottomland hardwood forest in South Carolina. The traps were placed at the centers, edges, and in the forest adjacent to gaps of different sizes (0.13, 0.26, and 0.50 ha) and ages (1 and 7 yr old) during four sampling periods in 2001. Overall, the...

Argonne OutLoud: "Climate Change: Fact, Fiction and What You Can Do"

ScienceCinema

Sisterson, Douglas

2018-06-07

Research meteorologist Doug Sisterson discusses climate change and the cutting-edge research taking place at Argonne as well as collaborative research with other institutions, including the University of Chicago.

The Future Is Coming: Electronic Health Records

MedlinePlus

... Current Issue Past Issues The Future Is Coming: Electronic Health Records Past Issues / Spring 2009 Table of ... special conference on the cutting-edge topic of electronic health records (EHR) on May 20-21, 2009, ...

21 CFR 882.5900 - Preformed craniosynostosis strip.

Code of Federal Regulations, 2012 CFR

2012-04-01

... craniosynostosis strip. (a) Identification. A preformed craniosynostosis strip is a plastic strip used to cover bone edges of craniectomy sites (sites where the skull has been cut) to prevent the bone from regrowing...

21 CFR 882.5900 - Preformed craniosynostosis strip.

Code of Federal Regulations, 2014 CFR

2014-04-01

... craniosynostosis strip. (a) Identification. A preformed craniosynostosis strip is a plastic strip used to cover bone edges of craniectomy sites (sites where the skull has been cut) to prevent the bone from regrowing...

21 CFR 882.5900 - Preformed craniosynostosis strip.

Code of Federal Regulations, 2013 CFR

2013-04-01

... craniosynostosis strip. (a) Identification. A preformed craniosynostosis strip is a plastic strip used to cover bone edges of craniectomy sites (sites where the skull has been cut) to prevent the bone from regrowing...

21 CFR 882.5900 - Preformed craniosynostosis strip.

Code of Federal Regulations, 2011 CFR

2011-04-01

... craniosynostosis strip. (a) Identification. A preformed craniosynostosis strip is a plastic strip used to cover bone edges of craniectomy sites (sites where the skull has been cut) to prevent the bone from regrowing...

How Stitches Help Kids Heal

MedlinePlus

... cuts is a small sticky strip called a butterfly bandage. It keeps the edges of a shallow ... help. Different kinds of materials — sutures, glue, and butterflies — need different kinds of care. The doctor probably ...

NASA Balloon Highlights 2015-2017

NASA Technical Reports Server (NTRS)

Fairbrother, Debora

2017-01-01

The NASA Balloon Program provides low-cost, quick response, near space access to NASAs science Community for conducting Cutting Edge Science Investigations. Serve as a technology development platform. Excellent training for NASA scientists and engineers.

SSBRP User Operations Facility (UOF) Overview and Development Strategy

NASA Technical Reports Server (NTRS)

Picinich, Lou; Stone, Thom; Sun, Charles; Windrem, May; Givens, John J. (Technical Monitor)

1995-01-01

This paper will present the Space Station Biological Research Project (SSBRP) User Operations Facility (UOF) architecture and development strategy. A major element of the UOF at NASA Ames Research Center, the Communication and Data System (CDS) will be the primary focus of the discussions. CDS operational, telescience, security, and development objectives will be discussed along with CDS implementation strategy. The implementation strategy discussions will include: Object Oriented Analysis & Design, System & Software Prototyping, and Technology Utilization. A CDS design overview that includes: CDS Context Diagram, CDS Architecture, Object Models, Use Cases, and User Interfaces will also be presented. CDS development brings together "cutting edge" technologies and techniques such as: object oriented development, network security, multimedia networking, web-based data distribution, JAVA, and graphical user interfaces. Use of these "cutting edge" technologies and techniques translates directly to lower development and operations costs.

Variability in Chemical Vapor Deposited Zinc Sulfide: Assessment of Legacy and International CVD ZnS Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCloy, John S.; Korenstein, Ralph

2009-10-06

Samples of CVD ZnS from the United States, Germany, Israel, and China were evaluated using transmission spectroscopy, x-ray diffraction, photoluminescence, and biaxial flexure testing. Visible and near-infrared scattering, 6 μm absorption, and ultraviolet cut-on edge varied substantially in tested materials. Crystallographic hexagonality and texture was determined and correlated with optical scattering. Transmission cut-on (ultraviolet edge) blue-shifts with annealing and corresponds to visible color but not the 6 μm absorption. Photoluminescence results suggest that CVD ZnS exhibits a complex suite of electronic bandgap defects. All CVD ZnS tested with biaxial flexure exhibit similar fracture strength values and Weibull moduli. This surveymore » suggests that technical understanding of the structure and optical properties CVD ZnS is still in its infancy.« less

Monitoring of peri-distal gastrectomy carbohydrate antigen 19-9 level in gastric juice and its significance

PubMed Central

Xu, A-Man; Huang, Lei; Han, Wen-Xiu; Wei, Zhi-Jian

2014-01-01

Gastric carcinoma is one of the most common and deadly malignancies nowadays, and carbohydrate antigen 19-9 (CA 19-9) in gastric juice has been rarely studied. To compare peri-distal gastrectomy (DG) gastric juice and serum CA 19-9 and reveal its significance, we selected 67 patients diagnosed with gastric carcinoma who underwent DG, and collected their perioperative gastric juice whose CA 19-9 was detected, with serum CA 19-9 monitored as a comparison. We found that: gastric juice CA 19-9 pre-gastrectomy was significantly correlated with tumor TNM classification, regarding tumor size, level of gastric wall invaded, differentiated grade and number of metastatic lymph nodes as influencing factors, while serum CA 19-9 revealed little information; gastric juice CA 19-9 was significantly correlated with radical degree, and regarded number of resected lymph nodes and classification of cutting edge as impact factors; thirteen patients whose gastric juice CA 19-9 rose post-DG showed features indicating poor prognosis; the difference of gastric juice CA 19-9 between pre- and post-gastrectomy was correlated with tumor TNM classification and radical degree, and regarded tumor size, number of resected metastatic and normal lymph nodes, sum of distances from tumor to cutting edges and classification of cutting edge as influential factors. We conclude that peri-DG gastric juice CA 19-9 reveals much information about tumor and radical gastrectomy, and may indicate prognosis; while serum CA 19-9 has limited significance. PMID:24482710

Laser circular cutting of Kevlar sheets: Analysis of thermal stress filed and assessment of cutting geometry

NASA Astrophysics Data System (ADS)

Yilbas, B. S.; Akhtar, S. S.; Karatas, C.

2017-11-01

A Kevlar laminate has negative thermal expansion coefficient, which makes it difficult to machine at room temperaures using the conventional cutting tools. Contararily, laser machining of a Kevlar laminate provides advantages over the conventional methods because of the non-mechanical contact between the cutting tool and the workpiece. In the present study, laser circular cutting of Kevlar laminate is considered. The experiment is carried out to examine and evaluate the cutting sections. Temperature and stress fields formed in the cutting section are simulated in line with the experimental study. The influence of hole diameters on temperature and stress fields are investigated incorporating two different hole diameters. It is found that the Kevlar laminate cutting section is free from large size asperities such as large scale sideways burnings and attachemnt of charred residues. The maximum temperature along the cutting circumference remains higher for the large diameter hole than that of the small diameter hole. Temperature decay is sharp around the cutting section in the region where the cutting terminates. This, in turn, results in high temperature gradients and the thermal strain in the cutting region. von Mises stress remains high in the region where temperature gradients are high. von Mises stress follows similar to the trend of temperature decay around the cutting edges.

The Legacy of Thomas Hodgkin Is Still Relevant 150 Years After His Death. Nothing of Humanity Was Foreign to Him.

PubMed

Dann, Eldad J

2017-01-30

Current leading figures in medical science usually focus on very specific topics and use cutting-edge technologies to broaden our knowledge in the field. The working environment of the nineteenth century was very different. Medical giants of that time such as Rudolph Virchow and Thomas Hodgkin had a wide-ranging scope of research and humanitarian interests and made enormous contributions to a variety of core areas of medicine and the well-being of mankind. The year 2016 marked the 150th anniversary of the death of Dr Thomas Hodgkin. Even a brief review of his life and work proves the current relevance of the outstanding deeds of this exceptional physician, medical educator, and defender of human rights for the poor and underprivileged; his vision was far ahead of his time.

Creative Turbulence: Experiments in Art and Physics

NASA Astrophysics Data System (ADS)

Fonda, Enrico; Dubois, R. Luke; Camnasio, Sara; Porfiri, Maurizio; Sreenivasan, Katepalli R.; Lathrop, Daniel P.; Serrano, Daniel; Ranjan, Devesh

2016-11-01

Effective communication of basic research to non-experts is necessary to inspire the public and to justify support for science by the taxpayers. The creative power of art is particularly important to engage an adult audience, who otherwise might not be receptive to standard didactic material. Interdisciplinarity defines new trends in research, and works at the intersection of art and science are growing in popularity, even though they are often isolated experiments. We present a public-facing collaboration between physicists/engineers performing research in fluid dynamics, and audiovisual artists working in cutting-edge media installation and performance. The result of this collaboration is a curated exhibition, with supporting public programming. We present the artworks, the lesson learned from the interactions between artists and scientists, the potential outreach impact and future developments. This project is supported by the APS Public Outreach Mini Grant.

Use of an holistic approach for effective adoption of User-Centred-Design techniques in diabetes disease management: Experiences in user need elicitation.

PubMed

Fico, Giuseppe; Arredondo, Maria Teresa

2015-01-01

One of the most important challenges of designing eHealth tools for Chronic Disease Management is to understand how transforming cutting-edge innovations in something that can impact the current clinical practice and improve the performance of the health care systems. The adoption of User Centered Design techniques is fundamental in order to integrate these systems in an effective and successful way. The work presented in this paper describe the methodologies used in the context of two multidisciplinary research projects, METABO and MOSAIC. The adoption of the methodologies have been driven by the CeHRes Roamap, a holistic framework that support participatory development of eHealth. The work reported in this paper describes the results of the first two (out of the five) phases in eliciting user needs.

Technologies Advance UAVs for Science, Military

NASA Technical Reports Server (NTRS)

2010-01-01

A Space Act Agreement with Goddard Space Flight Center and West Virginia University enabled Aurora Flight Sciences Corporation, of Manassas, Virginia, to develop cost-effective composite manufacturing capabilities and open a facility in West Virginia. The company now employs 160 workers at the plant, tasked with crafting airframe components for the Global Hawk unmanned aerial vehicle (UAV) program. While one third of the company's workforce focuses on Global Hawk production, the rest of the company develops advanced UAV technologies that are redefining traditional approaches to unmanned aviation. Since the company's founding, Aurora s cutting-edge work has been supported with funding from NASA's Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) programs.

Reducing Our Carbon Footprint: Frontiers in Climate Forecasting (LBNL Science at the Theater)

ScienceCinema

Collins, Bill [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2018-06-07

Bill Collins directs Berkeley Lab's research dedicated to atmospheric and climate science. Previously, he headed the development of one of the leading climate models used in international studies of global warming. His work has confirmed that man-made greenhouse gases are probably the main culprits of recent warming and future warming poses very real challenges for the environment and society. A lead author of the most recent assessment of the science of climate change by the United Nations' Intergovernmental Panel on Climate Change, Collins wants to create a new kind of climate model, one that will integrate cutting-edge climate science with accurate predictions people can use to plan their lives

Imitation and Innovation: The Dual Engines of Cultural Learning.

PubMed

Legare, Cristine H; Nielsen, Mark

2015-11-01

Imitation and innovation work in tandem to support cultural learning in children and facilitate our capacity for cumulative culture. Here we propose an integrated theoretical account of how the unique demands of acquiring instrumental skills and cultural conventions provide insight into when children imitate, when they innovate, and to what degree. For instrumental learning, with an increase in experience, high fidelity imitation decreases and innovation increases. By contrast, for conventional learning, imitative fidelity stays high, regardless of experience, and innovation stays low. We synthesize cutting edge research on the development of imitative flexibility and innovation to provide insight into the social learning mechanisms underpinning the uniquely human mind. Copyright © 2015 Elsevier Ltd. All rights reserved.

Our Environment in Miniature: Dust and the Early Twentieth-Century Forensic Imagination

PubMed Central

BURNEY, IAN

2013-01-01

This article explores the articulation of the crime scene as a distinct space of theory and practice in the early twentieth century. In particular it focuses on the evidentiary hopes invested in what would at first seem an unpromising forensic object: dust. Ubiquitous and, to the uninitiated, characterless, dust nevertheless featured as an exemplary object of cutting-edge forensic analysis in two contemporary domains: writings of criminologists and works of detective fiction. The article considers how in these texts dust came to mark the furthest reach of a new forensic capacity they were promoting, one that drew freely upon the imagination to invest crime scene traces with meaning. PMID:23766552

Radio frequency energy for non-invasive and minimally invasive skin tightening.

PubMed

Mulholland, R Stephen

2011-07-01

This article reviews the non-invasive and minimally invasive options for skin tightening, focusing on peer-reviewed articles and presentations and those technologies with the most proven or promising RF non-excisional skin-tightening results for excisional surgeons. RF has been the mainstay of non-invasive skin tightening and has emerged as the "cutting edge" technology in the minimally invasive skin-tightening field. Because these RF skin-tightening technologies are capital equipment purchases with a significant cost associated, this article also discusses some business issues and models that have proven to work in the plastic surgeon's office for non-invasive and minimally invasive skin-tightening technologies. Copyright © 2011 Elsevier Inc. All rights reserved.

Measurement of W + bb and a search for MSSM Higgs bosons with the CMS detector at the LHC

NASA Astrophysics Data System (ADS)

O'Connor, Alexander Pinpin

Tooling used to cure composite laminates in the aerospace and automotive industries must provide a dimensionally stable geometry throughout the thermal cycle applied during the part curing process. This requires that the Coefficient of Thermal Expansion (CTE) of the tooling materials match that of the composite being cured. The traditional tooling material for production applications is a nickel alloy. Poor machinability and high material costs increase the expense of metallic tooling made from nickel alloys such as 'Invar 36' or 'Invar 42'. Currently, metallic tooling is unable to meet the needs of applications requiring rapid affordable tooling solutions. In applications where the tooling is not required to have the durability provided by metals, such as for small area repair, an opportunity exists for non-metallic tooling materials like graphite, carbon foams, composites, or ceramics and machinable glasses. Nevertheless, efficient machining of brittle, non-metallic materials is challenging due to low ductility, porosity, and high hardness. The machining of a layup tool comprises a large portion of the final cost. Achieving maximum process economy requires optimization of the machining process in the given tooling material. Therefore, machinability of the tooling material is a critical aspect of the overall cost of the tool. In this work, three commercially available, brittle/porous, non-metallic candidate tooling materials were selected, namely: (AAC) Autoclaved Aerated Concrete, CB1100 ceramic block and Cfoam carbon foam. Machining tests were conducted in order to evaluate the machinability of these materials using end milling. Chip formation, cutting forces, cutting tool wear, machining induced damage, surface quality and surface integrity were investigated using High Speed Steel (HSS), carbide, diamond abrasive and Polycrystalline Diamond (PCD) cutting tools. Cutting forces were found to be random in magnitude, which was a result of material porosity. The abrasive nature of Cfoam produced rapid tool wear when using HSS and PCD type cutting tools. However, tool wear was not significant in AAC or CB1100 regardless of the type of cutting edge. Machining induced damage was observed in the form of macro-scale chipping and fracture in combination with micro-scale cracking. Transverse rupture test results revealed significant reductions in residual strength and damage tolerance in CB1100. In contrast, AAC and Cfoam showed no correlation between machining induced damage and a reduction in surface integrity. Cutting forces in machining were modeled for all materials. Cutting force regression models were developed based on Design of Experiment and Analysis of Variance. A mechanistic cutting force model was proposed based upon conventional end milling force models and statistical distributions of material porosity. In order to validate the model, predicted cutting forces were compared to experimental results. Predicted cutting forces agreed well with experimental measurements. Furthermore, over the range of cutting conditions tested, the proposed model was shown to have comparable predictive accuracy to empirically produced regression models; greatly reducing the number of cutting tests required to simulate cutting forces. Further, this work demonstrates a key adaptation of metallic cutting force models to brittle porous material; a vital step in the research into the machining of these materials using end milling.

Using Q-Chem on the Peregrine System | High-Performance Computing | NREL

Science.gov Websites

initio quantum chemistry package with special strengths in excited state methods, non-adiabatic coupling , solvation models, explicitly correlated wavefunction methods, and cutting-edge DFT. Running Q-Chem on

Technologies Taking Us There

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cotrell, Jason; Veers, Paul

2015-09-29

Keynote presentation at the Iowa State Wind Energy Symposium. This presentation examines several cutting-edge technologies and research being performed by the National Renewable Energy Laboratory that is helping achieve the U.S. Department of Energy's Wind Vision.

Research Publications.

ERIC Educational Resources Information Center

Yarbrough, Cornelia, Comp.

1994-01-01

Asserts that research can provide a cutting edge for the profession and essential information for teachers as they plan new instructional strategies, evaluation techniques, and advocacy efforts. Presents an annotated bibliography of 17 items related to music education research. (ACM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

The Lightweight Materials research and development (R&D) area within the DOE Vehicle Technologies Office (VTO) provides support and guidance for many cutting-edge automotive technologies under development. Research focuses on addressing critical barriers to commercializing lightweight materials for passenger and commercial vehicles.

ENVIRONMENTAL STATISTICS INITIATIVE

EPA Science Inventory

EPA's Center of Excellence (COE) for Environmental Computational Science is intended to integrate cutting-edge science and emerging information technology (IT) solutions for input to the decision-making process. Complementing the research goals of EPA's COE, the NERL has initiat...

LDSD Test Device Arrives in Hawaii

NASA Image and Video Library

2014-05-28

Engineers unload ground support equipment for a June engineering test flight above Kauai, Hawaii. The test flight is part of NASA LDSD project, which is investigating cutting-edge landing technologies that could fly on future Mars missions.

50 CFR 635.20 - Size limits.

Code of Federal Regulations, 2012 CFR

2012-10-01

... forward edge of the cut. (d) Billfish. (1) No person shall take, retain or possess a blue marlin taken... remain in effect through the end of the applicable fishing year or until otherwise adjusted. (e) Sharks...

50 CFR 635.20 - Size limits.

Code of Federal Regulations, 2013 CFR

2013-10-01

... forward edge of the cut. (d) Billfish. (1) No person shall take, retain or possess a blue marlin taken... remain in effect through the end of the applicable fishing year or until otherwise adjusted. (e) Sharks...

[Continuum based fast Fourier transform processing of infrared spectrum].

PubMed

Liu, Qing-Jie; Lin, Qi-Zhong; Wang, Qin-Jun; Li, Hui; Li, Shuai

2009-12-01

To recognize ground objects with infrared spectrum, high frequency noise removing is one of the most important phases in spectrum feature analysis and extraction. A new method for infrared spectrum preprocessing was given combining spectrum continuum processing and Fast Fourier Transform (CFFT). Continuum was firstly removed from the noise polluted infrared spectrum to standardize hyper-spectra. Then the spectrum was transformed into frequency domain (FD) with fast Fourier transform (FFT), separating noise information from target information After noise eliminating from useful information with a low-pass filter, the filtered FD spectrum was transformed into time domain (TD) with fast Fourier inverse transform. Finally the continuum was recovered to the spectrum, and the filtered infrared spectrum was achieved. Experiment was performed for chlorite spectrum in USGS polluted with two kinds of simulated white noise to validate the filtering ability of CFFT by contrast with cubic function of five point (CFFP) in time domain and traditional FFT in frequency domain. A circle of CFFP has limited filtering effect, so it should work much with more circles and consume more time to achieve better filtering result. As for conventional FFT, Gibbs phenomenon has great effect on preprocessing result at edge bands because of special character of rock or mineral spectra, while works well at middle bands. Mean squared error of CFFT is 0. 000 012 336 with cut-off frequency of 150, while that of FFT and CFFP is 0. 000 061 074 with cut-off frequency of 150 and 0.000 022 963 with 150 working circles respectively. Besides the filtering result of CFFT can be improved by adjusting the filter cut-off frequency, and has little effect on working time. The CFFT method overcomes the Gibbs problem of FFT in spectrum filtering, and can be more convenient, dependable, and effective than traditional TD filter methods.

Small arms ammunition

DOEpatents

Huerta, Joseph

1992-01-01

An elongate projectile for small arms use has a single unitary mass with a hollow nose cavity defined by a sharp rigid cutting edge adapted to make initial contact with the target surface and cut therethrough. The projectile then enters the target mass in an unstable flight mode. The projectile base is substantially solid such that the nose cavity, while relatively deep, does not extend entirely through the base and the projectile center of gravity is aft of its geometric center.

Cutting assembly including expanding wall segments of auger

DOEpatents

Treuhaft, Martin B.; Oser, Michael S.

1983-01-01

A mining auger comprises a cutting head carried at one end of a tubular shaft and a plurality of wall segments which in a first position thereof are disposed side by side around said shaft and in a second position thereof are disposed oblique to said shaft. A vane projects outwardly from each wall segment. When the wall segments are in their first position, the vanes together form a substantially continuous helical wall. A cutter is mounted on the peripheral edge of each of the vanes. When the wall segments are in their second position, the cutters on the vanes are disposed radially outward from the perimeter of the cutting head.

Tool wear analysis during duplex stainless steel trochoidal milling

NASA Astrophysics Data System (ADS)

Amaro, Paulo; Ferreira, Pedro; Simões, Fernando

2018-05-01

In this study a tool with interchangeable inserts of sintered carbides coated with AlTiN were used to mill a duplex stainless steel with trochoidal strategies. Cutting speed range from 120 to 300 m/min were used and t he evaluation of tool deterioration and tool life was made according international standard ISO 8688-1. It was observed a progressive development of a flank wear and a cumulative cyclic process of localized adhesion of the chip to the cutting edge, followed by chipping, loss of the coating and substrate exposure. The tool life reached a maximum of 35 min. for cutting speed of 120 m/min. However, it was possible to maintain a tool life of 20-25 minutes when the cutting speed was increased up to 240 m/min.

Green Turning of FCD 700 Ductile Cast Iron Using Coated Carbide Tool

NASA Astrophysics Data System (ADS)

Rodzi, Mohd Nor Azmi Mohd; Ghani, Jaharah A.; Eghawail, A. M.; Othman, Kamal; Rahman, Mohd. Nizam Ab.; Haron, Che Hassan Che

2010-10-01

This paper presents the performance of carbide coated cutting insert in turning FCD700 ductile cast iron in various dry machining conditions (without air, using air and chilled air). The turning parameters studied were, cutting speed of 120 m/min., feed rate of 0.15 mm/rev-0.4 mm/rev, and depth of cut of 0.6 mm-1.0 mm. The results show that the tool life was significantly controlled by the type of air coolant used, whereas the cutting force and surface roughness were not influenced by these coolants. Chilled air was found to be significantly improved the tool life by about 30% and 40% respectively when compared with normal air and without air conditions. The wear mechanism was predominantly controlled by the flank and crater wears on the flank and rake faces respectively. Due to the low cutting speed used in the experiment, both flank and crater wears were uniformly formed along the cutting edge and no catastrophic failure was observed under the scanning electron microscope (SEM).

Infectious Agents and Cancer Epidemiology Research Webinar Series

Cancer.gov

Infectious Agents and Cancer Epidemiology Research Webinar Series highlights emerging and cutting-edge research related to infection-associated cancers, shares scientific knowledge about technologies and methods, and fosters cross-disciplinary discussions on infectious agents and cancer epidemiology.

Biology Notes.

ERIC Educational Resources Information Center

School Science Review, 1982

1982-01-01

Describes laboratory procedures, demonstrations, and classroom activities/materials, including use of dwarf cichlids (fishes) in secondary school biology, teaching edge effects on stomatal diffusion, computer program on effects of selection on gene frequencies, biological oxidation/reduction reactions, short cuts with Drosophila, computer program…

CSE - International Workshop on Photon Tools for Combustion and Energy

Science.gov Websites

participants. A defining feature of the workshops is the promotion of free discussion about cutting edge and ; particle formation; sprays and applications of new technologies, e.g. free-electron laser sources

A sharp knife for high temperatures

NASA Technical Reports Server (NTRS)

Heisman, R. M.; Iceland, W. F.

1978-01-01

Electrically heated nickel-chrome-steel alloy knife may be used to cut heat resistant plastic felt and similar materials with relative ease. Blade made of commercially available alloy RA 330 retains edge at temperatures as high as 927 C.

Edge Supports for Photovoltaic Modules

NASA Technical Reports Server (NTRS)

Maloney, T. J.

1984-01-01

Mounting strips patterned after glazing gaskets. Easy to install supports for rooftop solar modules consist of extruded rubber mullions with locking zippers. Supports cut to length with utility knife and installed without special tools. Adaptable to many different roof configurations.

3 CFR 8807 - Proclamation 8807 of May 1, 2012. National Building Safety Month, 2012

Code of Federal Regulations, 2013 CFR

2013-01-01

... and standards, they help save lives and prevent disruption in the wake of disaster. Resilient..., withstand, and recover from disasters. We are drawing upon cutting edge science and technology to establish...

Solving Graph Laplacian Systems Through Recursive Bisections and Two-Grid Preconditioning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ponce, Colin; Vassilevski, Panayot S.

2016-02-18

We present a parallelizable direct method for computing the solution to graph Laplacian-based linear systems derived from graphs that can be hierarchically bipartitioned with small edge cuts. For a graph of size n with constant-size edge cuts, our method decomposes a graph Laplacian in time O(n log n), and then uses that decomposition to perform a linear solve in time O(n log n). We then use the developed technique to design a preconditioner for graph Laplacians that do not have this property. Finally, we augment this preconditioner with a two-grid method that accounts for much of the preconditioner's weaknesses. Wemore » present an analysis of this method, as well as a general theorem for the condition number of a general class of two-grid support graph-based preconditioners. Numerical experiments illustrate the performance of the studied methods.« less

Rupture disc

DOEpatents

Newton, Robert G.

1977-01-01

The intermediate heat transport system for a sodium-cooled fast breeder reactor includes a device for rapidly draining the sodium therefrom should a sodium-water reaction occur within the system. This device includes a rupturable member in a drain line in the system and means for cutting a large opening therein and for positively removing the sheared-out portion from the opening cut in the rupturable member. According to the preferred embodiment of the invention the rupturable member includes a solid head seated in the end of the drain line having a rim extending peripherally therearound, the rim being clamped against the end of the drain line by a clamp ring having an interior shearing edge, the bottom of the rupturable member being convex and extending into the drain line. Means are provided to draw the rupturable member away from the drain line against the shearing edge to clear the drain line for outflow of sodium therethrough.

Hidden dental diversity in the oldest terrestrial apex predator Dimetrodon.

PubMed

Brink, Kirstin S; Reisz, Robert R

2014-01-01

Paleozoic sphenacodontid synapsids are the oldest known fully terrestrial apex predators. Dimetrodon and other sphenacodontids are the first terrestrial vertebrates to have strong heterodonty, massive skulls and well-developed labio-lingually compressed and recurved teeth with mesial and distal cutting edges (carinae). Here we reveal that the dentition of Dimetrodon and other sphenacodontids is diverse. Tooth morphology includes simple carinae with smooth cutting edges and elaborate enamel features, including the first occurrence of cusps and true denticles (ziphodonty) in the fossil record. A time-calibrated phylogenetic analysis indicates that changes in dental morphology occur in the absence of any significant changes in skull morphology, suggesting that the morphological change is associated with changes in feeding style and trophic interactions in these ecosystems. In addition, the available evidence indicates that ziphodonty evolved for the first time in the largest known species of the genus Dimetrodon and independently from the ziphodont teeth observed in some therapsids.

Effect of the Leveling Conditions on Residual Stress Evolution of Hot Rolled High Strength Steels for Cold Forming

NASA Astrophysics Data System (ADS)

Park, Keecheol; Oh, Kyungsuk

2017-09-01

In order to investigate the effect of leveling conditions on residual stress evolution during the leveling process of hot rolled high strength steels, the in-plane residual stresses of sheet processed under controlled conditions at skin-pass mill and levelers were measured by cutting method. The residual stress was localized near the edge of sheet. As the thickness of sheet was increased, the residual stress occurred region was expanded. The magnitude of residual stress within the sheet was reduced as increasing the deformation occurred during the leveling process. But the residual stress itself was not removed completely. The magnitude of camber occurred at cut plate was able to be predicted by the residual stress distribution. A numerical algorithm was developed for analysing the effect of leveling conditions on residual stress. It was able to implement the effect of plastic deformation in leveling, tension, work roll bending, and initial state of sheet (residual stress and curl distribution). The validity of simulated results was verified from comparison with the experimentally measured residual stress and curl in a sheet.

Cultural Resources Survey of Mobile Harbor, Alabama.

DTIC Science & Technology

1983-01-01

improvement from the point of view of supply and communication with other European settlements, since it cut the lightering distance to the capital in half...order to cut the costs of building (Bathe 1978:08.00-02; Millar 1978:15-29). 32 6e The sharing of ship builders, the borrowing of vessel lines and the... Eslava Street Mobile. Burned to water’s edge during overhaul. Notes: Served as HINGHAM in Boston Harbor; served as ORIENT in Long Island Sound. Operated

11. AERIAL VIEW OF CROSSCUT FACILITY, LOOKING NORTH. THE HYDRO ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. AERIAL VIEW OF CROSSCUT FACILITY, LOOKING NORTH. THE HYDRO PLANT CENTER SITS ON THE EDGE OF RAVINE WHICH IS ACTUALLY THE BEGINNING OF THE GRAND CANAL. THE CROSS-CUT STEAM PLANT IS THE LARGE WHITE BUILDING JUST WEST OF THE HYDRO PLANT, WITH THE TRANSMISSION SWITCHYARD IN BETWEEN. THE OTHER BUILDINGS ARE SALT RIVER PROJECT FABRICATION AND EQUIPMENT SHOPS Photographer unknown, August 22, 1958 - Cross Cut Hydro Plant, North Side of Salt River, Tempe, Maricopa County, AZ

The Space Laser Business Model

NASA Technical Reports Server (NTRS)

2005-01-01

Creating long-duration, high-powered lasers, for satellites, that can withstand the type of optical misalignment and damage dished out by the unforgiving environment of space, is work that is unique to NASA. It is complicated, specific work, where each step forward is into uncharted territory. In the 1990s, as this technology was first being created, NASA gave free reign to a group of "laser jocks" to develop their own business model and supply the Space Agency with the technology it needed. It was still to be a part of NASA as a division of Goddard Space Flight Center, but would operate independently out of a remote office. The idea for this satellite laboratory was based on the Skunk Works concept at Lockheed Martin Corporation. Formerly known as the Lockheed Corporation, in 1943, the aerospace firm, realizing that the type of advanced research it needed done could not be performed within the confines of a larger company, allowed a group of researchers and engineers to essentially run their own microbusiness without the corporate oversight. The Skunk Works project, in Burbank, California, produced America s first jet fighter, the world s most successful spy plane (U-2), the first 3-times-the-speed-of-sound surveillance aircraft, and the F-117A Nighthawk Stealth Fighter. Boeing followed suit with its Phantom Works, an advanced research and development branch of the company that operates independent of the larger unit and is responsible for a great deal of its most cutting-edge research. NASA s version of this advanced business model was the Space Lidar Technology Center (SLTC), just south of Goddard, in College Park, Maryland. Established in 1998 under a Cooperative Agreement between Goddard and the University of Maryland s A. James Clark School of Engineering, it was a high-tech laser shop where a small group of specialists, never more than 20 employees, worked all hours of the day and night to create the cutting- edge technology the Agency required of them. Drs. Robert Afzal and Joseph Dallas were directors of the SLTC, and led the development and production of active spaceborne, remote-sensing, optical instruments. As a pioneer in the area of photonics, Dr. Dallas led basic research, development, and production of semiconductor laser diode products, improving coupling efficiency through novel physical optics modeling and intracavity phase-correction techniques. He worked for NASA for 15 years, 11 of which were as a civil servant, and 4 of which were as a contractor.

High speed turning of compacted graphite iron using controlled modulation

NASA Astrophysics Data System (ADS)

Stalbaum, Tyler Paul

Compacted graphite iron (CGI) is a material which emerged as a candidate material to replace cast iron (CI) in the automotive industry for engine block castings. Its thermal and mechanical properties allow the CGI-based engines to operate at higher cylinder pressures and temperatures than CI-based engines, allowing for lower fuel emissions and increased fuel economy. However, these same properties together with the thermomechanical wear mode in the CGI-CBN system result in poor machinability and inhibit CGI from seeing wide spread use in the automotive industry. In industry, machining of CGI is done only at low speeds, less than V = 200 m/min, to avoid encountering rapid wear of the cutting tools during cutting. Studies have suggested intermittent cutting operations such as milling suffer less severe tool wear than continuous cutting. Furthermore, evidence that a hard sulfide layer which forms over the cutting edge in machining CI at high speeds is absent during machining CGI is a major factor in the difference in machinability of these material systems. The present study addresses both of these issues by modification to the conventional machining process to allow intermittent continuous cutting. The application of controlled modulation superimposed onto the cutting process -- modulation-assisted machining (MAM) -- is shown to be quite effective in reducing the wear of cubic boron nitride (CBN) tools when machining CGI at high machining speeds (> 500 m/min). The tool life is at least 20 times greater than found in conventional machining of CGI. This significant reduction in wear is a consequence of reduction in the severity of the tool-work contact conditions with MAM. The propensity for thermochemical wear of CBN is thus reduced. It is found that higher cutting speed (> 700 m/min) leads to lower tool wear with MAM. The MAM configuration employing feed-direction modulation appears feasible for implementation at high speeds and offers a solution to this challenging class of industrial machining applications. This study's approach is by series of high speed turning tests of CGI with CBN tools, comparing conventional machining to MAM for similar parameters otherwise, by tool wear measurements and machinability observations.

Gating geometry studies of thin-walled 17-4PH investment castings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maguire, M.C.; Zanner, F.J.

1992-11-01

The ability to design gating systems that reliably feed and support investment castings is often the result of ``cut-and-try`` methodology. Factors such as hot tearing, porosity, cold shuts, misruns, and shrink are defects often corrected by several empirical gating design iterations. Sandia National Laboratories is developing rules that aid in removing the uncertainty involved in the design of gating systems for investment castings. In this work, gating geometries used for filling of thin walled investment cast 17-4PH stainless steel flat plates were investigated. A full factorial experiment evaluating the influence of metal pour temperature, mold preheat temperature, and mold channelmore » thickness were conducted for orientations that filled a horizontal flat plate from the edge. A single wedge gate geometry was used for the edge-gated configuration. Thermocouples placed along the top of the mold recorded metal front temperatures, and a real-time x-ray imaging system tracked the fluid flow behavior during filling of the casting. Data from these experiments were used to determine the terminal fill volumes and terminal fill times for each gate design.« less

Gating geometry studies of thin-walled 17-4PH investment castings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maguire, M.C.; Zanner, F.J.

1992-01-01

The ability to design gating systems that reliably feed and support investment castings is often the result of cut-and-try'' methodology. Factors such as hot tearing, porosity, cold shuts, misruns, and shrink are defects often corrected by several empirical gating design iterations. Sandia National Laboratories is developing rules that aid in removing the uncertainty involved in the design of gating systems for investment castings. In this work, gating geometries used for filling of thin walled investment cast 17-4PH stainless steel flat plates were investigated. A full factorial experiment evaluating the influence of metal pour temperature, mold preheat temperature, and mold channelmore » thickness were conducted for orientations that filled a horizontal flat plate from the edge. A single wedge gate geometry was used for the edge-gated configuration. Thermocouples placed along the top of the mold recorded metal front temperatures, and a real-time x-ray imaging system tracked the fluid flow behavior during filling of the casting. Data from these experiments were used to determine the terminal fill volumes and terminal fill times for each gate design.« less

Study on Platinum Coating Depth in Focused Ion Beam Diamond Cutting Tool Milling and Methods for Removing Platinum Layer.

PubMed

Choi, Woong Kirl; Baek, Seung Yub

2015-09-22

In recent years, nanomachining has attracted increasing attention in advanced manufacturing science and technologies as a value-added processes to control material structures, components, devices, and nanoscale systems. To make sub-micro patterns on these products, micro/nanoscale single-crystal diamond cutting tools are essential. Popular non-contact methods for the macro/micro processing of diamond composites are pulsed laser ablation (PLA) and electric discharge machining (EDM). However, for manufacturing nanoscale diamond tools, these machining methods are not appropriate. Despite diamond's extreme physical properties, diamond can be micro/nano machined relatively easily using a focused ion beam (FIB) technique. In the FIB milling process, the surface properties of the diamond cutting tool is affected by the amorphous damage layer caused by the FIB gallium ion collision and implantation and these influence the diamond cutting tool edge sharpness and increase the processing procedures. To protect the diamond substrate, a protection layer-platinum (Pt) coating is essential in diamond FIB milling. In this study, the depth of Pt coating layer which could decrease process-induced damage during FIB fabrication is investigated, along with methods for removing the Pt coating layer on diamond tools. The optimum Pt coating depth has been confirmed, which is very important for maintaining cutting tool edge sharpness and decreasing processing procedures. The ultra-precision grinding method and etching with aqua regia method have been investigated for removing the Pt coating layer. Experimental results show that when the diamond cutting tool width is bigger than 500 nm, ultra-precision grinding method is appropriate for removing Pt coating layer on diamond tool. However, the ultra-precision grinding method is not recommended for removing the Pt coating layer when the cutting tool width is smaller than 500 nm, because the possibility that the diamond cutting tool is damaged by the grinding process will be increased. Despite the etching method requiring more procedures to remove the Pt coating layer after FIB milling, it is a feasible method for diamond tools with under 500 nm width.

Intensive Survey at 11-Jd-126, Jo Daviess County, Illinois. Volume 1.

DTIC Science & Technology

1983-07-01

out. The joints between the roofing is also plastered; carefully covered about a foot thick with grass which we cut with our . knives, & four or...plaster had been pushed or smeared up against the walls or joints provide opportunities to reconstruct the diameter of the lath or withes in ,-any...of the sherds has one fairly complete edge and a small fracture on the opposing side from the opposite edge (see Figure 56), one can estimate an

Hot compression process for making edge seals for fuel cells

DOEpatents

Dunyak, Thomas J.; Granata, Jr., Samuel J.

1994-01-01

A hot compression process for forming integral edge seals in anode and cade assemblies wherein the assemblies are made to a nominal size larger than a finished size, beads of AFLAS are applied to a band adjacent the peripheral margins on both sides of the assemblies, the assemblies are placed in a hot press and compressed for about five minutes with a force sufficient to permeate the peripheral margins with the AFLAS, cooled and cut to finished size.

EPA Science Matters Newsletter: Volume 2, Number 4

EPA Pesticide Factsheets

While continuing to advance the kinds of cutting edge research efforts that are the hallmark of EPA, we also are taking ambitious steps to ensure that we are as effective as we can be for the American people.

Wyoming Department of Transportation (WYDOT) road condition reporting application for weather responsive traffic management.

DOT National Transportation Integrated Search

2015-10-01

Federal Highway Administrations (FHWA) Road Weather Management Program (RWMP) strives to promote the development and implementation of cutting-edge techniques for maintaining safety, mobility, and productivity of roadways during adverse weather co...

Thermal Imaging in the Science Classroom

ERIC Educational Resources Information Center

Short, Daniel B.

2012-01-01

Thermal cameras are useful tools for use in scientific investigation and for teaching scientific concepts to students in the classroom. Demonstrations of scientific phenomena can be greatly enhanced visually by the use of this cutting-edge technology. (Contains 7 figures.)

Applications of Proteomic Technologies to Toxicology

EPA Science Inventory

Proteomics is the large-scale study of gene expression at the protein level. This cutting edge technology has been extensively applied to toxicology research recently. The up-to-date development of proteomics has presented the toxicology community with an unprecedented opportunit...

Michigan Department of Transportation (MDOT) weather responsive traveler information (Wx-TINFO) system implementation project.

DOT National Transportation Integrated Search

2016-01-01

Federal Highway Administrations (FHWA) Road Weather Management Program (RWMP) strives to promote the development and implementation of cutting-edge techniques for maintaining safety, mobility, and productivity of roadways during adverse weather co...

South Dakota Department of Transportation (SDDOT) regional traveler information system for weather responsive traffic management.

DOT National Transportation Integrated Search

2015-11-01

Federal Highway Administrations (FHWA) Road Weather Management Program (RWMP) strives to promote the development and implementation of cutting-edge techniques for maintaining safety, mobility, and productivity of roadways during adverse weather co...

EPA Science Matters Newsletter: Volume 2, Number 4

EPA Pesticide Factsheets

2017-02-14

While continuing to advance the kinds of cutting edge research efforts that are the hallmark of EPA, we also are taking ambitious steps to ensure that we are as effective as we can be for the American people.

In-Q-Tel, the strategic investment firm for the U.S. Intelligence Community

NASA Astrophysics Data System (ADS)

Ulvick, S. J.; Tighe, D. W.

2008-04-01

In-Q-Tel is a strategic investment firm that works to identify, adapt, and deliver innovative technology solutions to support the missions of the Central Intelligence Agency and the broader U.S. Intelligence Community (IC). Launched by the CIA in 1999 as a private, independent, not-for-profit organization, IQT's mission is to identify and partner with companies developing cutting-edge technologies that serve the national security interests of the United States. Working from an evolving strategic blueprint defining the Intelligence Community's critical technology needs, IQT engages with entrepreneurs, growth companies, researchers, and venture capitalists to deliver technologies that provide superior capabilities for the CIA and the broader IC. To date, IQT has reviewed more than 6,300 business proposals, invested in more than 100 companies, and delivered more than 140 technology solutions to the U.S. Intelligence Community.

Studies on nanosecond 532nm and 355nm and ultrafast 515nm and 532nm laser cutting super-hard materials

NASA Astrophysics Data System (ADS)

Zhang, Jie; Tao, Sha; Wang, Brian; Zhao, Jay

2017-02-01

In this paper, micro-processing of three kinds of super-hard materials of poly-crystal diamond (PCD)/tungsten-carbide (WC), CVD-diamond and cubic boron nitride (CNB) has been systematically studied using nanosecond laser (532nm and 355nm), and ultrafast laser (532nm and 515nm). Our purpose is to investigate a full laser micro-cutting solution to achieve a ready-to-use cutting tool insert (CTI). The results show a clean cut with little burns and recasting at edge. The cutting speed of 2-10mm/min depending on thickness was obtained. The laser ablation process was also studied by varying laser parameters (wavelength, pulse width, pulse energy, repetition rate) and tool path to improve cutting speed. Also, studies on material removal efficiency (MRE) of PCD/WC with 355nm-ns and 515nm-fs laser as a function of laser fluence show that 355nm-ns laser is able to achieve higher MRE for PCD and WC. Thus, ultrafast laser is not necessarily used for superhard material cutting. Instead, post-polishing with ultrafast laser can be used to clean cutting surface and improve smoothness.

Transient beam oscillation with a highly dynamic scanner for laser beam fusion cutting

NASA Astrophysics Data System (ADS)

Goppold, Cindy; Pinder, Thomas; Herwig, Patrick

2016-02-01

Sheet metals with thicknesses >8 mm have a distinct cutting performance. The free choice of the optical configuration composed of fiber diameter, collimation, and focal length offers many opportunities to influence the static beam geometry. Previous analysis points out the limitations of this method in the thick section area. Within the present study, an experimental investigation of fiber laser fusion cutting of 12 mm stainless steel was performed by means of dynamical beam oscillation. Two standard optical setups are combined with a highly dynamic galvano-driven scanner that achieves frequencies up to 4 kHz. Dependencies of the scanner parameter, the optical circumstances, and the conventional cutting parameters are discussed. The aim is to characterize the capabilities and challenges of the dynamic beam shaping in comparison to the state-of-the-art static beam shaping. Thus, the trials are evaluated by quality criteria of the cut edge as surface roughness and burr height, the feed rate, and the cut kerf geometry. The investigation emphasizes promising procedural possibilities for improvements of the cutting performance in the case of fiber laser fusion cutting of thick stainless steel by means of the application of a highly dynamic scanner.

Ratio of Cut Surface Area to Leaf Sample Volume for Water Potential Measurements by Thermocouple Psychrometers

PubMed Central

Walker, Sue; Oosterhuis, Derrick M.; Wiebe, Herman H.

1984-01-01

Evaporative losses from the cut edge of leaf samples are of considerable importance in measurements of leaf water potential using thermocouple psychrometers. The ratio of cut surface area to leaf sample volume (area to volume ratio) has been used to give an estimate of possible effects of evaporative loss in relation to sample size. A wide range of sample sizes with different area to volume ratios has been used. Our results using Glycine max L. Merr. cv Bragg indicate that leaf samples with area to volume values less than 0.2 square millimeter per cubic millimeter give psychrometric leaf water potential measurements that compare favorably with pressure chamber measurements. PMID:16663578

Accidental cut-throat injuries from the broken windshield of an auto rickshaw: Two unusual cases.

PubMed

Swain, Rajanikanta; Dhaka, Shivani; Sharma, Munish; Bakshi, Mantaran Singh; Murty, O P; Sikary, Asit Kumar

2018-01-01

Accidental cut-throat injuries are extremely rare and usually involve a sharp-edged weapon. In this paper, two cases of a cut-throat wound to two auto-rickshaw drivers are presented where the broken windshield of the auto-rickshaws was responsible for the wounds. In both the cases, fatal incised wounds were present over the neck, cutting the soft tissue along with the major vessels. The death occurred due to exsanguination caused by neck-vessel injury in one case and trachea along with neck-vessel injury in the second case. Although the wounds on the neck initially suggested homicide, they were found to have occurred accidentally as a result of a road traffic accident involving a head-on collision of auto rickshaws. The injuries were inflicted by the shattered glass of the windshield.

Apparatus and process for removing a predetermined portion of reflective material from mirror

DOEpatents

Perry, Stephen J.; Steinmetz, Lloyd L.

1994-01-01

An apparatus and process are disclosed for removal of a stripe of soft reflective material of uniform width from the surface of a mirror by using a blade having a large included angle to inhibit curling of the blade during the cutting operation which could result in damage to the glass substrate of the mirror. The cutting blade is maintained at a low blade angle with respect to the mirror surface to produce minimal chipping along the cut edge and to minimize the force exerted on the coating normal to the glass surface which could deform the flat mirror. The mirror is mounted in a cutting mechanism containing a movable carriage on which the blade is mounted to provide very accurate straightness of the travel of the blade along the mirror.

Cutting-edge technologies: GPS/Satellite communications-based tracking

USDA-ARS?s Scientific Manuscript database

Despite wide-spread adoption of GPS and satellite-communication technologies within the freight and transportation industries, commercially-available telemetry tracking systems have not kept pace with the evolving demands of ecological research. Commercial GPS tracking collars are costly ($1,500 to...

Investigate plow blade optimization.

DOT National Transportation Integrated Search

2015-08-01

The main technique for removing accumulated snow from roadways is through the use of snow plows and snow plow : blades (blades), or cutting edges. The blade is bolted to the snow plow, and it is the component of the plowing system that : makes contac...

Strategic Plan for the ORD National Exposure Research Laboratory (NERL)

EPA Science Inventory

The National Exposure Research Laboratory (NERL) has a valued reputation for supporting the Agency’s mission of protecting human health and the environment with multidisciplinary expertise that brings cutting-edge research and technology to address critical exposure questions and...

Development of a computer controlled underbody plow.

DOT National Transportation Integrated Search

2007-01-01

Underbody plows can be very useful tools in winter maintenance, especially when compacted snow or hard ice must be removed from the roadway. By the application of significant down-force, and the use of an appropriate cutting edge angle, compacted sno...

No Limit: Exploring the Science of the Universe

ScienceCinema

Meinecke, Jena; Remington, Bruce; Zylstra, Alex; Falcone, Roger; Rinderknecht, Hans; Casner, Alexis

2018-06-13

Scientists who conduct unique, cutting-edge Discovery Science experiments on Lawrence Livermore National Laboratory’s National Ignition Facility (NIF) describe the excitement of doing research on the world’s largest and highest-energy laser system.

Argonne News Brief: Cutting-Edge Science Makes 3D Printing More Efficient and Reliable

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Argonne National Laboratory researchers are gaining a deeper understanding of the 3D printing process, and as a result, they are helping industries quickly and economically manufacture 3D-printed products that are truly reliable.

EPA's Research at the Cutting Edge of Exposure Science

EPA Science Inventory

EPA’s National Exposure Research Laboratory (NERL) serves as the lead for exposure science across U.S. Federal agencies. Exposure science has gained importance with increased appreciation of environmental influences on population disease burden. At a time when population ...

Big Physics at Small Places: The Mongol Horde Model of Undergraduate Research

ERIC Educational Resources Information Center

Voss, Philip J.; Finck, Joseph E.; Howes, Ruth H.; Brown, James; Baumann, Thomas; Schiller, Andreas; Thoennessen, Michael; DeYoung, Paul A.; Peaslee, Graham F.; Hinnefeld, Jerry; Luther, Bryan; Pancella, Paul V.; Rogers, Warren F.

2008-01-01

A model for engaging undergraduates in cutting-edge experimental nuclear physics research at a national user facility is discussed. Methods to involve students and examples of their success are presented. (Contains 2 figures and 3 tables.)

3 CFR 8466 - Proclamation 8466 of December 16, 2009. Wright Brothers Day, 2009

Code of Federal Regulations, 2010 CFR

2010-01-01

.... In these challenging times, the story of Orville and Wilbur Wright reminds us of what can be... future powered by cutting-edge ideas and new technologies, we celebrate this day by looking back to the...

SU-E-J-252: Reproducibility of Radiogenomic Image Features: Comparison of Two Semi-Automated Segmentation Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, M; Woo, B; Kim, J

Purpose: Objective and reliable quantification of imaging phenotype is an essential part of radiogenomic studies. We compared the reproducibility of two semi-automatic segmentation methods for quantitative image phenotyping in magnetic resonance imaging (MRI) of glioblastoma multiforme (GBM). Methods: MRI examinations with T1 post-gadolinium and FLAIR sequences of 10 GBM patients were downloaded from the Cancer Image Archive site. Two semi-automatic segmentation tools with different algorithms (deformable model and grow cut method) were used to segment contrast enhancement, necrosis and edema regions by two independent observers. A total of 21 imaging features consisting of area and edge groups were extracted automaticallymore » from the segmented tumor. The inter-observer variability and coefficient of variation (COV) were calculated to evaluate the reproducibility. Results: Inter-observer correlations and coefficient of variation of imaging features with the deformable model ranged from 0.953 to 0.999 and 2.1% to 9.2%, respectively, and the grow cut method ranged from 0.799 to 0.976 and 3.5% to 26.6%, respectively. Coefficient of variation for especially important features which were previously reported as predictive of patient survival were: 3.4% with deformable model and 7.4% with grow cut method for the proportion of contrast enhanced tumor region; 5.5% with deformable model and 25.7% with grow cut method for the proportion of necrosis; and 2.1% with deformable model and 4.4% with grow cut method for edge sharpness of tumor on CE-T1W1. Conclusion: Comparison of two semi-automated tumor segmentation techniques shows reliable image feature extraction for radiogenomic analysis of GBM patients with multiparametric Brain MRI.« less

NASA Astrophysics EPO Community: Enhancing STEM Experience of Undergraduates

NASA Astrophysics Data System (ADS)

Manning, J.; Meinke, B. K.; Lawton, B.; Smith, D. A.; Bartolone, L.; Schultz, G.; NASA Astrophysics EPO Community

2015-11-01

The NASA Science Mission Directorate (SMD) Astrophysics Education and Public Outreach (EPO) community and Forum work together to capitalize on the cutting-edge discoveries of NASA Astrophysics missions to enhance the Science, Technology, Engineering, and Math (STEM) experience of undergraduates. The NASA SMD Astrophysics EPO community has proven expertise in providing both professional development and resources to faculty at two- and four-year institutions and in offering internships and student collaboration opportunities. These mission- and grant-based EPO programs are uniquely poised to foster collaboration between scientists with content expertise and educators with pedagogy expertise. We present examples of how the NASA Astrophysics EPO community and Forum engage the higher education community in these ways, including associated metrics and evaluation findings.

FY2013 Advanced Power Electronics and Electric Motors R&D Annual Progress Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, Susan A.

The Advanced Power Electronics and Electric Motors (APEEM) technology area within the DOE Vehicle Technologies Office (VTO) provides support and guidance for many cutting-edge automotive technologies now under development. Research is focused on developing revolutionary new power electronics (PE), electric motor, and traction drive system (TDS) technologies that will leapfrog current on-the-road technologies, leading to lower cost and better efficiency in transforming battery energy to useful work. The research and development (R&D) is also aimed at achieving a greater understanding of and improvements in the way the various new components of tomorrow’s automobiles will function as a unified system tomore » improve fuel efficiency through research in more efficient TDSs.« less

Science at the Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

White, Nicholas E.

2012-01-01

The Sciences and Exploration Directorate of the NASA Goddard Space Flight Center (GSFC) is the largest Earth and space science research organization in the world. Its scientists advance understanding of the Earth and its life-sustaining environment, the Sun, the solar system, and the wider universe beyond. Researchers in the Sciences and Exploration Directorate work with engineers, computer programmers, technologists, and other team members to develop the cutting-edge technology needed for space-based research. Instruments are also deployed on aircraft, balloons, and Earth's surface. I will give an overview of the current research activities and programs at GSFC including the James Web Space Telescope (JWST), future Earth Observing programs, experiments that are exploring our solar system and studying the interaction of the Sun with the Earth's magnetosphere.

Study on Crystallographic Orientation Effect on Surface Generation of Aluminum in Nano-cutting

NASA Astrophysics Data System (ADS)

Xu, Feifei; Fang, Fengzhou; Zhu, Yuanqing; Zhang, Xiaodong

2017-04-01

The material characteristics such as size effect are one of the most important factors that could not be neglected in cutting the material at nanoscale. The effects of anisotropic nature of single crystal materials in nano-cutting are investigated employing the molecular dynamics simulation. Results show that the size effect of the plastic deformation is based on different plastic carriers, such as the twin, stacking faults, and dislocations. The minimum uncut chip thickness is dependent on cutting direction, where even a negative value is obtained when the cutting direction is {110}<001>. It also determines the material deformation and removal mechanism (e.g., shearing, extruding, and rubbing mechanism) with a decrease in uncut chip thickness. When material is deformed by shearing, the primary shearing zone expands from the stagnation point or the tip of stagnation zone. When a material is deformed by extruding and rubbing, the primary deformation zone almost parallels to the cutting direction and expands from the bottom of the cutting edge merging with the tertiary deformation zone. The generated surface quality relates to the crystallographic orientation and the minimum uncut chip thickness. The cutting directions of {110}<001>, {110}<1-10>, and {111}<1-10>, whose minimum uncut chip thickness is relatively small, have better surface qualities compared to the other cutting direction.

Study on Crystallographic Orientation Effect on Surface Generation of Aluminum in Nano-cutting.

PubMed

Xu, Feifei; Fang, Fengzhou; Zhu, Yuanqing; Zhang, Xiaodong

2017-12-01

The material characteristics such as size effect are one of the most important factors that could not be neglected in cutting the material at nanoscale. The effects of anisotropic nature of single crystal materials in nano-cutting are investigated employing the molecular dynamics simulation. Results show that the size effect of the plastic deformation is based on different plastic carriers, such as the twin, stacking faults, and dislocations. The minimum uncut chip thickness is dependent on cutting direction, where even a negative value is obtained when the cutting direction is {110}<001>. It also determines the material deformation and removal mechanism (e.g., shearing, extruding, and rubbing mechanism) with a decrease in uncut chip thickness. When material is deformed by shearing, the primary shearing zone expands from the stagnation point or the tip of stagnation zone. When a material is deformed by extruding and rubbing, the primary deformation zone almost parallels to the cutting direction and expands from the bottom of the cutting edge merging with the tertiary deformation zone. The generated surface quality relates to the crystallographic orientation and the minimum uncut chip thickness. The cutting directions of {110}<001>, {110}<1-10>, and {111}<1-10>, whose minimum uncut chip thickness is relatively small, have better surface qualities compared to the other cutting direction.

Plywood Inlays Thourgh CO2 Laser Cutting

NASA Astrophysics Data System (ADS)

Pires, Margarida C.; Araujo, J. L.; Teixeira, M. Ribau; Rodrigues, F. Carvalho

1989-07-01

Furniture with inlays is rather expensive. This is so on two accounts: Firstly, furniture with inlays is generally manufactured with solid wood.Secondly,wood carving and figure cutting are both time consuming and they produce a high rate of rejections. To add to it all the cutting and carving of minute figures requires an outstanding craftmanship. In fact the craftman is in most instance the artist and also the manufacturer. While desiring that the high artistic level is maintained in the industry the search for new method to produce inlays for furniture in not son expensive materials and to produce them in a repetitive and flexible way laser cutting of plywood was found to be quite suitable. This paper presents the charts for CO2 laser cutting of both positive and negatives in several types of plywood. The main problem is not so much the cutting of the positive and negatives pieces but to be able to cut the piece in a way that the fitting is done without any problems caused by the ever present charring effect, which takes palce at the edges of the cut pieces. To minimise this aspect positive and negative pieces have to be cut under stringent focusing conditions and with slight different scales. The condittions for our machine are presented.

Excitons in scintillator materials: Optical properties and electron-energy loss spectra of NaI, LaBr 3, BaI 2, and SrI 2

DOE PAGES

Schleife, Andre; Zhang, Xiao; Li, Qi; ...

2016-11-03

In this paper, materials for scintillator radiation detectors need to fulfill a diverse set of requirements such as radiation hardness and highly specific response to incoming radiation, rendering them a target of current materials design efforts. Even though they are amenable to cutting-edge theoretical spectroscopy techniques, surprisingly many fundamental properties of scintillator materials are still unknown or not well explored. In this work, we use first-principles approaches to thoroughly study the optical properties of four scintillator materials: NaI, LaBr 3, BaI 2, and SrI 2. By solving the Bethe–Salpeter equation for the optical polarization function we study the influence ofmore » excitonic effects on dielectric and electron-energy loss functions. This work sheds light into fundamental optical properties of these four scintillator materials and lays the ground-work for future work that is geared toward accurate modeling and computational materials design of advanced radiation detectors with unprecedented energy resolution.« less

SSC San Diego Brief 2002

DTIC Science & Technology

2002-01-01

information dominance . We are at the cutting edge of the processes of transforming data into information, information into knowledge, and knowledge into...solutions for warrior information dominance . We intend to continue and expand SSC San Diego’s leadership in defining, developing, integrating, installing, and

High Performance Computing and Cutting-Edge Analysis Can Open New

Science.gov Websites

Realms March 1, 2018 Two people looking at a 3D interactive graphical data the Visualization Center in capabilities to visualize complex, 3D images of the wakes from multiple wind turbines so that we can better

On the Cutting Edge with Gene Splicing.

ERIC Educational Resources Information Center

Ehrman, Patrick; Fritz, Lucie

1989-01-01

Describes a program in which second-year biology students use plasmid isolation to remove DNA from Escherichia coli bacteria and subsequently ligate and transform it into other E. coli bacteria. Cites ways teachers can get involved in current research that allows student participation. (RT)

Be an Alumni Relations Revolutionary.

ERIC Educational Resources Information Center

Bickel, Kathy

2000-01-01

Presents marketing guru Guy Kawasaki's seven rules for revolutionaries, and examples of alumni relations innovators who are implementing change with cutting-edge programs, services, and business practices. Rules include: "jump curves" (look for new paths); "break down barriers" (challenge roadblocks of ignorance and inertia);…

On the Cutting Edge: Movements and Institutional Examples of Technological Disruption

ERIC Educational Resources Information Center

Leon, Marjorie Roth; Price, Todd Alan

2016-01-01

This chapter describes technological disruptions in higher education that pose challenges and offer opportunities to college and university students, faculty, and administrators. It provides examples of innovative responses being explored by 2-year and 4-year higher education institutions.

Riding the Cutting Edge

ERIC Educational Resources Information Center

Freit-Hammes, Lori

2007-01-01

When Western Wisconsin Technical College created the Health Benefits Improvement Team, they had no experience with the complexity and ever-changing demands of health care and its associated costs. See how they've embraced their mission and are changing the way business is done in their community.

Selected Analytical Methods for Environmental Remediation and Recovery (SAM) Presentation for APHL

EPA Science Inventory

The US Environmental Protection Agency’s Office of Research and Development (ORD) conducts cutting-edge research that provides the underpinning of science and technology for public health and environmental policies and decisions made by federal, state and other governmental...

Sandia National Laboratories: National Security Missions: Defense Systems

Science.gov Websites

Technology Partnerships Business, Industry, & Non-Profits Government Universities Center for Development Agreement (CRADA) Strategic Partnership Projects, Non-Federal Entity (SPP/NFE) Agreements New leadership for the national security community by delivering cutting-edge experimental and operational sensor

Advanced Space Flight and Environmental Concerns

NASA Technical Reports Server (NTRS)

Whitaker, A.

2001-01-01

The aerospace industry has conquered numerous environmental challenges during the last decade. The aerospace industry of today has evolved due in part to the environmental challenges, becoming stronger, more robust, learning to push the limits of technology, materials and manufacturing, and performing cutting edge engineering.

3 CFR 8711 - Proclamation 8711 of September 12, 2011. National Health Information Technology Week, 2011

Code of Federal Regulations, 2012 CFR

2012-01-01

... economy forward and improved the lives of our people, from the industrial innovations of the nineteenth century to today’s cutting-edge science. Progress in our Nation’s health care system is no different, and...

WORKSHOP ON MINING IMPACTED NATIVE AMERICAN LANDS CD

EPA Science Inventory

Multimedia Technology is an exciting mix of cutting-edge Information Technologies that utilize a variety of interactive structures, digital video and audio technologies, 3-D animation, high-end graphics, and peer-reviewed content that are then combined in a variety of user-friend...

Habitat edge, land management, and rates of brood parasitism in tallgrass prairie.

PubMed

Patten, Michael A; Shochat, Eyal; Reinking, Dan L; Wolfe, Donald H; Sherrod, Steve K

2006-04-01

Bird populations in North America's grasslands have declined sharply in recent decades. These declines are traceable, in large part, to habitat loss, but management of tallgrass prairie also has an impact. An indirect source of decline potentially associated with management is brood parasitism by the Brown-headed Cowbird (Molothrus ater), which has had substantial negative impacts on many passerine hosts. Using a novel application of regression trees, we analyzed an extensive five-year set of nest data to test how management of tallgrass prairie affected rates of brood parasitism. We examined seven landscape features that may have been associated with parasitism: presence of edge, burning, or grazing, and distance of the nest from woody vegetation, water, roads, or fences. All five grassland passerines that we included in the analyses exhibited evidence of an edge effect: the Grasshopper Sparrow (Ammodramus savannarum), Henslow's Sparrow (A. henslowii), Dickcissel (Spiza americana), Red-winged Blackbird (Agelaius phoeniceus), and Eastern Meadowlark (Sturnella magna). The edge was represented by narrow strips of woody vegetation occurring along roadsides cut through tallgrass prairie. The sparrows avoided nesting along these woody edges, whereas the other three species experienced significantly higher (1.9-5.3x) rates of parasitism along edges than in prairie. The edge effect could be related directly to increase in parasitism rate with decreased distance from woody vegetation. After accounting for edge effect in these three species, we found evidence for significantly higher (2.5-10.5x) rates of parasitism in grazed plots, particularly those burned in spring to increase forage, than in undisturbed prairie. Regression tree analysis proved to be an important tool for hierarchically parsing various landscape features that affect parasitism rates. We conclude that, on the Great Plains, rates of brood parasitism are strongly associated with relatively recent road cuts, in that edge effects manifest themselves through the presence of trees, a novel habitat component in much of the tallgrass prairie. Grazing is also a key associate of increased parasitism. Areas managed with prescribed fire, used frequently to increase forage for grazing cattle, may experience higher rates of brood parasitism. Regardless, removing trees and shrubs along roadsides and refraining from planting them along new roads may benefit grassland birds.

Prediction of thermal cycling induced cracking in polymer matrix composites

NASA Technical Reports Server (NTRS)

Mcmanus, Hugh L.

1993-01-01

This report summarizes the work done in the period February 1993 through July 1993 on the 'Prediction of Thermal Cycling Induced Cracking In Polymer Matrix Composites' program. An oral presentation of this work was given to Langley personnel in September of 1993. This document was prepared for archival purposes. Progress studies have been performed on the effects of spatial variations in material strength. Qualitative agreement was found with observed patterns of crack distribution. These results were presented to NASA Langley personnel in November 1992. The analytical methodology developed by Prof. McManus in the summer of 1992 (under an ASEE fellowship) has been generalized. A method for predicting matrix cracking due to decreasing temperatures and/or thermal cycling in all plies of an arbitrary laminate has been implemented as a computer code. The code also predicts changes in properties due to the cracking. Experimental progressive cracking studies on a variety of laminates were carried out at Langley Research Center. Results were correlated to predictions using the new methods. Results were initially mixed. This motivated an exploration of the configuration of cracks within laminates. A crack configuration study was carried out by cutting and/or sanding specimens in order to examine the distribution of cracks within the specimens. These investigations were supplemented by dye-penetrant enhanced X-ray photographs. The behavior of thin plies was found to be different from the behavior of thicker plies (or ply groups) on which existing theories are based. Significant edge effects were also noted, which caused the traditional metric of microcracking (count of cracks on a polished edge) to be very inaccurate in some cases. With edge and configuration taken into account, rough agreement with predictions was achieved. All results to date were reviewed with NASA Langley personnel in September 1993.

Freeform manufacturing of a microoptical lens array on a steep curved substrate by use of a voice coil fast tool servo.

PubMed

Scheiding, Sebastian; Yi, Allen Y; Gebhardt, Andreas; Li, Lei; Risse, Stefan; Eberhardt, Ramona; Tünnermann, Andreas

2011-11-21

We report what is to our knowledge the first approach to diamond turn microoptical lens array on a steep curved substrate by use of a voice coil fast tool servo. In recent years ultraprecision machining has been employed to manufacture accurate optical components with 3D structure for beam shaping, imaging and nonimaging applications. As a result, geometries that are difficult or impossible to manufacture using lithographic techniques might be fabricated using small diamond tools with well defined cutting edges. These 3D structures show no rotational symmetry, but rather high frequency asymmetric features thus can be treated as freeform geometries. To transfer the 3D surface data with the high frequency freeform features into a numerical control code for machining, the commonly piecewise differentiable surfaces are represented as a cloud of individual points. Based on this numeric data, the tool radius correction is calculated to account for the cutting-edge geometry. Discontinuities of the cutting tool locations due to abrupt slope changes on the substrate surface are bridged using cubic spline interpolation.When superimposed with the trajectory of the rotationally symmetric substrate the complete microoptical geometry in 3D space is established. Details of the fabrication process and performance evaluation are described. © 2011 Optical Society of America

Assessment of penetrating thermal tissue damage/spread associated with PhotonBlade™, Valleylab™ Pencil, Valleylab™ EDGE™ Coated Pencil, PlasmaBlade® 3.0S and PlasmaBlade® 4.0 for intraoperative tissue dissection using the fresh extirpated porcine muscle model

NASA Astrophysics Data System (ADS)

Bennett, Haydon E.; Taylor, Scott D.; Fugett, James H.; Shrout, Joshua L.; Davison, Paul O.; Ryan, S. Eric; Coad, James E.

2017-02-01

Penetrating thermal tissue damage/spread is an important aspect of many electrosurgical devices and correlates with effective tissue cutting, hemostasis, preservation of adjacent critical structures and tissue healing. This study compared the thermal damage/spread associated with the PhotonBlade, Valleylab Pencil, Valleylab EDGE Coated Pencil, PlasmaBlade 3.0S and PlasmaBlade 4.0, when performing a single pass dynamic tissue cut in fresh extirpated porcine longissimus muscle. These devices were used in a fashion that emulated their use in the clinical setting. Each device's thermal damage/spread, at Minimum, Median and Maximum power input settings, was assessed with nitroblue tetrazolium viability staining in the WVU Pathology Laboratory for Translational Medicine. The thermal damage/spread associated with the PhotonBlade was compared with the other devices tested based on the individual treatment results (n=179 cuts combined). In summary, the PhotonBlade overall demonstrated the least penetrating thermal tissue damage/spread, followed by the PlasmaBlade 4.0, then Valleylab Pencil and PlasmaBlade 3.0S and then Valleylab EDGE Coated Pencil in order of increasing thermal damage/spread depths.

An experimental investigation on orthogonal cutting of hybrid CFRP/Ti stacks

NASA Astrophysics Data System (ADS)

Xu, Jinyang; El Mansori, Mohamed

2016-10-01

Hybrid CFRP/Ti stack has been widely used in the modern aerospace industry owing to its superior mechanical/physical properties and excellent structural functions. Several applications require mechanical machining of these hybrid composite stacks in order to achieve dimensional accuracy and assembly performance. However, machining of such composite-to-metal alliance is usually an extremely challenging task in the manufacturing sectors due to the disparate natures of each stacked constituent and their respective poor machinability. Special issues may arise from the high force/heat generation, severe subsurface damage and rapid tool wear. To study the fundamental mechanisms controlling the bi-material machining, this paper presented an experimental study on orthogonal cutting of hybrid CFRP/Ti stack by using superior polycrystalline diamond (PCD) tipped tools. The utilized cutting parameters for hybrid CFRP/Ti machining were rigorously adopted through a compromise selection due to the disparate machinability behaviors of the CFRP laminate and Ti alloy. The key cutting responses in terms of cutting force generation, machined surface quality and tool wear mechanism were precisely addressed. The experimental results highlighted the involved five stages of CFRP/Ti cutting and the predominant crater wear and edge fracture failure governing the PCD cutting process.

Development of AISI 316L stainless steel coronary stent

NASA Astrophysics Data System (ADS)

García-López, Erika; Siller, Héctor R.; Rodríguez, Ciro A.

2018-02-01

Coronary stents are manufactured through a sequence of processes and each step demands the process control to assure surface quality. This study is focused on the influence of laser cutting parameters and electropolishing on average surface roughness and back wall dross percentage for fiber laser cutting of AISI 316L coronary struts. A preliminary test and a design of experiments (DOE) were implemented to determine the limiting cutting conditions and the effect of these parameters on quality indicators. Preliminary results identify four cutting zones from a non-cut zone to a burned zone, in a frequency range between 1000 and 1500 Hz and a peak power between 160 to 180 W for clean cuts. From the DOE results, several interactions between factors were observed; however, a laser frequency of 1000 to 1500 Hz and a cutting speed of 250 mm/min minimize the backwall dross percentage and the surface roughness to values less than 2% and 0.9 μm, respectively. After the laser conditions selection, coronary stents were manufactured and electropolished to reduce the surface roughness on the strut edge. Electropolishing results indicate a surface roughness reduction from 0.9 μm to 0.3 μm after 300 s of electropolishing time.

Root dentine and endodontic instrumentation: cutting edge microscopic imaging

PubMed Central

2016-01-01

Cutting of the dental hard tissues is an integral part of restorative dentistry. Cutting of the root dentine is also needed in preparation prior to endodontic treatment, with significant commercial investment for the development of flexible cutting instruments based around nickel titanium (NiTi) alloys. This paper describes the evolution of endodontic cutting instruments, both in materials used, e.g. the transition from stainless steel to NiTi, and the design of the actual instruments themselves and their method of activation—by hand or motor driven. We have been examining tooth-cutting interactions microscopically for over 25 years using a variety of microscopic techniques; in particular, video-rate confocal microscopy. This has given a unique insight into how many of the procedures that we take for granted are achieved in clinical practice, by showing microscopic video images of the cutting as it occurs within the tooth. This technology has now been extended to allow imaging of the endodontic instrument and the root canal wall for the first time. We are able to image dentine distortion and crack propagation during endodontic filing of the root canal space. We are also able to visualize the often claimed, but seldom seen action of contemporary endodontic instruments. PMID:27274802

Root dentine and endodontic instrumentation: cutting edge microscopic imaging.

PubMed

Atmeh, Amre R; Watson, Timothy F

2016-06-06

Cutting of the dental hard tissues is an integral part of restorative dentistry. Cutting of the root dentine is also needed in preparation prior to endodontic treatment, with significant commercial investment for the development of flexible cutting instruments based around nickel titanium (NiTi) alloys. This paper describes the evolution of endodontic cutting instruments, both in materials used, e.g. the transition from stainless steel to NiTi, and the design of the actual instruments themselves and their method of activation-by hand or motor driven. We have been examining tooth-cutting interactions microscopically for over 25 years using a variety of microscopic techniques; in particular, video-rate confocal microscopy. This has given a unique insight into how many of the procedures that we take for granted are achieved in clinical practice, by showing microscopic video images of the cutting as it occurs within the tooth. This technology has now been extended to allow imaging of the endodontic instrument and the root canal wall for the first time. We are able to image dentine distortion and crack propagation during endodontic filing of the root canal space. We are also able to visualize the often claimed, but seldom seen action of contemporary endodontic instruments.

Herbivorous insect response to group selection cutting in a southeastern bottomland hardwood forest.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michael D. Ulyshen; James L. Hanula; Scott Horn

2005-04-01

ABSTRACT Malaise and pitfall traps were used to sample herbivorous insects in canopy gaps created by group-selection cutting in a bottomland hardwood forest in South Carolina. The traps were placed at the centers, edges, and in the forest adjacent to gaps of different sizes (0.13, 0.26, and 0.50 ha) and ages (1 and 7 yr old) during four sampling periods in 2001. Overall, the abundance and species richness of insect herbivores were greater at the centers of young gaps than at the edge of young gaps or in the forest surrounding young gaps. There were no differences in abundance ormore » species richness among old gap locations (i.e., centers, edges, and forest), and we collected significantly more insects in young gaps than old gaps. The insect communities in old gaps were more similar to the forests surrounding them than young gap communities were to their respective forest locations, but the insect communities in the two forests locations (surrounding young and old gaps) had the highest percent similarity of all. Although both abundance and richness increased in the centers of young gaps with increasing gap size, these differences were not significant.Weattribute the increased numbers of herbivorous insects to the greater abundance of herbaceous plants available in young gaps.« less

Detecting trends in academic research from a citation network using network representation learning

PubMed Central

Mori, Junichiro; Ochi, Masanao; Sakata, Ichiro

2018-01-01

Several network features and information retrieval methods have been proposed to elucidate the structure of citation networks and to detect important nodes. However, it is difficult to retrieve information related to trends in an academic field and to detect cutting-edge areas from the citation network. In this paper, we propose a novel framework that detects the trend as the growth direction of a citation network using network representation learning(NRL). We presume that the linear growth of citation network in latent space obtained by NRL is the result of the iterative edge additional process of a citation network. On APS datasets and papers of some domains of the Web of Science, we confirm the existence of trends by observing that an academic field grows in a specific direction linearly in latent space. Next, we calculate each node’s degree of trend-following as an indicator called the intrinsic publication year (IPY). As a result, there is a correlation between the indicator and the number of future citations. Furthermore, a word frequently used in the abstracts of cutting-edge papers (high-IPY paper) is likely to be used often in future publications. These results confirm the validity of the detected trend for predicting citation network growth. PMID:29782521

Cycle/Cocycle Oblique Projections on Oriented Graphs

NASA Astrophysics Data System (ADS)

Polettini, Matteo

2015-01-01

It is well known that the edge vector space of an oriented graph can be decomposed in terms of cycles and cocycles (alias cuts, or bonds), and that a basis for the cycle and the cocycle spaces can be generated by adding and removing edges to an arbitrarily chosen spanning tree. In this paper, we show that the edge vector space can also be decomposed in terms of cycles and the generating edges of cocycles (called cochords), or of cocycles and the generating edges of cycles (called chords). From this observation follows a construction in terms of oblique complementary projection operators. We employ this algebraic construction to prove several properties of unweighted Kirchhoff-Symanzik matrices, encoding the mutual superposition between cycles and cocycles. In particular, we prove that dual matrices of planar graphs have the same spectrum (up to multiplicities). We briefly comment on how this construction provides a refined formalization of Kirchhoff's mesh analysis of electrical circuits, which has lately been applied to generic thermodynamic networks.

Observation of three-dimensional internal structure of steel materials by means of serial sectioning with ultrasonic elliptical vibration cutting.

PubMed

Fujisaki, K; Yokota, H; Nakatsuchi, H; Yamagata, Y; Nishikawa, T; Udagawa, T; Makinouchi, A

2010-01-01

A three-dimensional (3D) internal structure observation system based on serial sectioning was developed from an ultrasonic elliptical vibration cutting device and an optical microscope combined with a high-precision positioning device. For bearing steel samples, the cutting device created mirrored surfaces suitable for optical metallography, even for long-cutting distances during serial sectioning of these ferrous materials. Serial sectioning progressed automatically by means of numerical control. The system was used to observe inclusions in steel materials on a scale of several tens of micrometers. Three specimens containing inclusions were prepared from bearing steels. These inclusions could be detected as two-dimensional (2D) sectional images with resolution better than 1 mum. A three-dimensional (3D) model of each inclusion was reconstructed from the 2D serial images. The microscopic 3D models had sharp edges and complicated surfaces.

Beaming Your School into the 21st Century.

ERIC Educational Resources Information Center

Pfeifer, R. Scott; Robb, Rick

2001-01-01

Mindsurf Networks--a partnership involving a suburban Baltimore high school, Sylvan Ventures, and Aether Systems--provides a cutting-edge, reasonably priced, networked mobile computing platform for learning. Handheld computers help students solve problems and beam information to teachers and each other. Partnership initiation strategies for…

Using Interactive Science Notebooks for Inquiry-Based Science

ERIC Educational Resources Information Center

Chesbro, Robert

2006-01-01

The interactive science notebook (ISN) is a perfect opportunity for science educators to encapsulate and promote the most cutting-edge constructivist teaching strategies while simultaneously addressing standards, differentiation of instruction, literacy development, and maintenance of an organized notebook as laboratory and field scientists do.…

Inaugural Technology Showcase Aims to Increase Industry Partnerships and Commercialization of Cancer-Related Inventions | FNLCR Staging

Cancer.gov

Biotechnology stakeholders from across the region will have the opportunity to learn about cutting-edge technologies addressing urgent and intractable problems in cancer research at the 2017 Technology Showcase, to be held at the Frederick National

Immersive Technologies and Language Learning

ERIC Educational Resources Information Center

Blyth, Carl

2018-01-01

This article briefly traces the historical conceptualization of linguistic and cultural immersion through technological applications, from the early days of locally networked computers to the cutting-edge technologies known as virtual reality and augmented reality. Next, the article explores the challenges of immersive technologies for the field…

NASA at the Space & Science Festival

NASA Image and Video Library

2017-08-05

NASA exhibits line Pier 86 during the Intrepid Space & Science Festival, Saturday, Aug. 5, 2017 held at the Intrepid Sea, Air & Space Museum in New York City. The week-long festival featured talks, films and cutting-edge displays showcasing NASA technology. Photo Credit: (NASA/Bill Ingalls)

EPA'S PARTNERSHIP WITH AWMA'S EM MAGAZINE: AN OUTREACH MODEL

EPA Science Inventory

EPA has many cutting edge research products that can help environmental professionals protect human health and the environment. However, these professionals can only use research tools of which they are aware. If research results are published yet not highlighted well to target a...

Future Directions in Distance Learning and Communication Technologies

ERIC Educational Resources Information Center

Shih, Timothy; Hung, Jason

2007-01-01

Future Directions in Distance Learning and Communication Technologies presents theoretical studies and practical solutions for engineers, educational professionals, and graduate students in the research areas of e-learning, distance education, and instructional design. This book provides readers with cutting-edge solutions and research directions…

Digitizing and Securing Archived Laboratory Notebooks

ERIC Educational Resources Information Center

Caporizzo, Marilyn

2008-01-01

The Information Group at Millipore has been successfully using a digital rights management tool to secure the email distribution of archived laboratory notebooks. Millipore is a life science leader providing cutting-edge technologies, tools, and services for bioscience research and biopharmaceutical manufacturing. Consisting of four full-time…

All Aboard! For a Lesson on Magnetic Levitated Trains.

ERIC Educational Resources Information Center

Moore, Virginia S.; Kaszas, William J.

1995-01-01

Presents an activity that explores the operation of Maglev trains. Demonstrates that elementary students can master cutting-edge technology through creating and racing magnetic vehicles on a specially designed track, researching the history of rail transportation, and exploring a current science issue. (NB)

Measuring the Value of AI in Space Science and Exploration

NASA Astrophysics Data System (ADS)

Blair, B.; Parr, J.; Diamond, B.; Pittman, B.; Rasky, D.

2017-10-01

FDL is tackling knowledge gaps useful to the space program by forming small teams of industrial partners, cutting-edge AI researchers and space science domain experts, and tasking them to solve problems that are important to NASA as well as humanity's future.

Inspiring Future Scientists

ERIC Educational Resources Information Center

Betteley, Pat; Lee, Richard E., Jr.

2009-01-01

In an integrated science/language arts/technology unit called "How Scientists Learn," students researched famous scientists from the past and cutting-edge modern-day scientists. Using biography trade books and the internet, students collected and recorded data on charts, summarized important information, and inferred meaning from text. Then they…

TUBE SHEARING VALVE

DOEpatents

Wilner, L.B.

1960-05-24

Explosive operated valves can be used to join two or more containers in fluid flow relationship, one such container being a sealed reservoir. The valve is most simply disposed by mounting it on the reservoir so thst a tube extends from the interior of the reservoir through the valve body, terminating at the bottom of the bore in a closed end; other containers may be similarly connected or may be open connected, as desired. The piston of the valve has a cutting edge at its lower end which shears off the closed tube ends and a recess above the cutting edge to provide a flow channel. Intermixing of the fluid being transferred with the explosion gases is prevented by a copper ring at the top of the piston which is force fitted into the bore at the beginning of the stroke. Although designed to avoid backing up of the piston at pressures up to 10,000 psi in the transferred fluid, proper operation is independent of piston position, once the tube ends were sheared.

Skype Me! Astronomers, Students, and Cutting-Edge Research

NASA Astrophysics Data System (ADS)

Hickox, Ryan C.; Gauthier, Adrienne J.

2014-06-01

A primary goal of many university science courses is to promote understanding of the process of contemporary scientific inquiry. One powerful way to achieve this is for students to explore current research and then interact directly with the leading scientist, the feasibility of which has recently increased dramatically due to free online video communication tools. We report on a program implemented at Dartmouth College in which students connect with a guest astronomer through Skype (video chat). The Skype session is wrapped in a larger activity where students explore current research articles, interact with the astronomer, and then reflect on the experience. The in-class Skype discussions require a small time commitment from scientists (20-30 minutes, with little or no need for preparation) while providing students direct access to researchers at the cutting edge of modern astronomy. We outline the procedures used to implement these discussions, and present qualitative assessments of student's understanding of the process of research, as well as feedback from the guest astronomers.

Bringing cutting-edge Earth and ocean sciences to under-served and rural audiences through informal science education

NASA Astrophysics Data System (ADS)

Cooper, S. K.; Petronotis, K. E.; Ferraro, C.; Johnson, K. T. M.; Yarincik, K.

2017-12-01

The International Ocean Discovery Program (IODP) is an international marine research collaboration that explores Earth's history and dynamics using ocean-going research platforms to recover data recorded in seafloor sediments and rocks and to monitor subseafloor environments. The JOIDES Resolution is the flagship vessel of IODP and is operated by the National Science Foundation. It is an inspirational hook for STEM Earth and ocean topics for children and the general public of all ages, but is not easily accessible due to its international travels and infrequent U.S. port calls. In response, a consortium of partners has created the Pop-Up/Drill Down Science project. The multi-year project, funded by NSF's Advancing Informal Science Learning program, aims to bring the JR and its science to under-served and rural populations throughout the country. Consisting of an inflatable walk-through ship, a multi-media experience, a giant interactive seafloor map and a series of interactive exhibit kiosks, the exhibit, entitled, In Search of Earth's Secrets: A Pop-Up Science Encounter, will travel to 12 communities throughout the next four years. In each community, the project will partner with local institutions like public libraries and small museums as hosts and to train local Girl Scouts to serve as exhibit facilitators. By working with local communities to select events and venues for pop-up events, the project hopes to bring cutting edge Earth and ocean science in creative new ways to underserved populations and inspire diverse audiences to explore further. This presentation will provide details of the project's goals, objectives and development and provide avenues to become involved.

Analysis of soft magnetic materials by electron backscatter diffraction as a powerful tool

NASA Astrophysics Data System (ADS)

Schuller, David; Hohs, Dominic; Loeffler, Ralf; Bernthaler, Timo; Goll, Dagmar; Schneider, Gerhard

2018-04-01

The current work demonstrates that electron backscatter diffraction (EBSD) is a powerful and versatile characterization technique for investigating soft magnetic materials. The properties of soft magnets, e.g., magnetic losses strongly depend on the materials chemical composition and microstructure, including grain size and shape, texture, degree of plastic deformation and elastic strain. In electrical sheet stacks for e-motor applications, the quality of the machined edges/surfaces of each individual sheet is of special interest. Using EBSD, the influence of the punching process on the microstructure at the cutting edge is quantitatively assessed by evaluating the crystallographic misorientation distribution of the deformed grains. Using an industrial punching process, the maximum affected deformation depth is determined to be 200 - 300 μm. In the case of laser cutting, the affected deformation depth is determined to be approximately zero. Reliability and detection limits of the developed EBSD approach are evaluated on non-affected sample regions and model samples containing different indentation test bodies. A second application case is the investigation of the recrystallization process during the annealing step of soft magnetic composites (SMC) toroids produced by powder metallurgy as a function of compaction pressure, annealing parameters and powder particle size. With increasing pressure and temperature, the recrystallized area fraction (e.g., grains with crystallographic misorientations < 3°) increases from 71 % (200 MPa, 800°C) to 90% (800 MPa, 800°C). Recrystallization of the compacted powder material starts at the particle boundaries or areas with existing plastic deformation. The progress of recrystallization is visualized as a function of time and of different particle to grain size distributions. Here, large particles with coarse internal grain structures show a favorable recrystallization behavior which results in large bulk permeability of up to 600 - 700 and lower amount of residual misorientations (>3°).

Modeling the forces of cutting with scissors.

PubMed

Mahvash, Mohsen; Voo, Liming M; Kim, Diana; Jeung, Kristin; Wainer, Joshua; Okamura, Allison M

2008-03-01

Modeling forces applied to scissors during cutting of biological materials is useful for surgical simulation. Previous approaches to haptic display of scissor cutting are based on recording and replaying measured data. This paper presents an analytical model based on the concepts of contact mechanics and fracture mechanics to calculate forces applied to scissors during cutting of a slab of material. The model considers the process of cutting as a sequence of deformation and fracture phases. During deformation phases, forces applied to the scissors are calculated from a torque-angle response model synthesized from measurement data multiplied by a ratio that depends on the position of the cutting crack edge and the curve of the blades. Using the principle of conservation of energy, the forces of fracture are related to the fracture toughness of the material and the geometry of the blades of the scissors. The forces applied to scissors generally include high-frequency fluctuations. We show that the analytical model accurately predicts the average applied force. The cutting model is computationally efficient, so it can be used for real-time computations such as haptic rendering. Experimental results from cutting samples of paper, plastic, cloth, and chicken skin confirm the model, and the model is rendered in a haptic virtual environment.

Parametric measurements of the effect of in-duct orifice edge shape on its noise damping performance

NASA Astrophysics Data System (ADS)

Ji, Chenzhen; Zhao, Dan; Han, Nuomin; Li, Jing

2016-12-01

Acoustic liners perforated with thousands of millimeter-size orifices are widely used in aero-engines and gas turbine engines as an effective noise damper. In this work, experimental investigations of the acoustic damping effect of in-duct perforated orifices are performed on a cold-flow pipe. A mean flow (also known as bias flow) is applied and its flow rate is variable. Emphasis is placed on the effect of the orifice edge shape. For this, 16 in-duct orifices with different edge shapes and porosities are designed and manufactured by using 3D printing technology and conventional laser cutting technique. The damping effect of these in-duct orifices is characterized by using power absorption coefficient Δ and reflection coefficient χ from 100 to 1000 Hz. The performances of these orifices are found to be either improved or deteriorated, depending on (1) edge shape, (2) the ratio T/d of orifice thickness to its diameter, (3) the bias flow Mach number, (4) downstream pipe length Ld and (5) porosity η via varying either the number N or surface area Ao of the orifices. In addition, modifying orifice edge does not lead to an increase of power absorption at lower frequency (⩽ 700 Hz). However, as the frequency is increased, the orifice with square (S-type) edge is found to be associated with 10 percent more power absorption. It is interesting to find that T/d over the tested range (≤ 0.5) has little influence on its damping capacity. However, the mean bias flow Mach number Ma and porosity η are shown to play critical roles on determining the noise damping performance of these orifices. Maximum power absorption Δmax is found to occur at Ma ≈ 0.018, while the optimum porosity corresponding to Δmax is approximately 7 percent. The present parametric measurements shed light on the roles of orifice edge shape, porosity and mean flow on its noise damping capacity, and facilitate the design of effective perforated liners.

Controllable Edge Feature Sharpening for Dental Applications

PubMed Central

2014-01-01

This paper presents a new approach to sharpen blurred edge features in scanned tooth preparation surfaces generated by structured-light scanners. It aims to efficiently enhance the edge features so that the embedded feature lines can be easily identified in dental CAD systems, and to avoid unnatural oversharpening geometry. We first separate the feature regions using graph-cut segmentation, which does not require a user-defined threshold. Then, we filter the face normal vectors to propagate the geometry from the smooth region to the feature region. In order to control the degree of the sharpness, we propose a feature distance measure which is based on normal tensor voting. Finally, the vertex positions are updated according to the modified face normal vectors. We have applied the approach to scanned tooth preparation models. The results show that the blurred edge features are enhanced without unnatural oversharpening geometry. PMID:24741376

Controllable edge feature sharpening for dental applications.

PubMed

Fan, Ran; Jin, Xiaogang

2014-01-01

This paper presents a new approach to sharpen blurred edge features in scanned tooth preparation surfaces generated by structured-light scanners. It aims to efficiently enhance the edge features so that the embedded feature lines can be easily identified in dental CAD systems, and to avoid unnatural oversharpening geometry. We first separate the feature regions using graph-cut segmentation, which does not require a user-defined threshold. Then, we filter the face normal vectors to propagate the geometry from the smooth region to the feature region. In order to control the degree of the sharpness, we propose a feature distance measure which is based on normal tensor voting. Finally, the vertex positions are updated according to the modified face normal vectors. We have applied the approach to scanned tooth preparation models. The results show that the blurred edge features are enhanced without unnatural oversharpening geometry.

Technological support of tool wear resistant qualities and cost saving of process of planetary grinding of flat parts

NASA Astrophysics Data System (ADS)

Ivanova, T. N.; Lyupa, D. C.; Revenko, N. F.; Berkutova, T. A.; Silivanova, O. A.

2018-03-01

A lot of factors varied in time lead to instability of the grinding process. Besides, the method of grinding influences significantly the productivity and quality of processing. In this regard a creation of processes of intensive defect-free grinding on the basis of new constructive and technology solutions represents the scientific problem which is of great importance. One of such solutions is application of planetary face grinding which allows simultaneously changing the kinematics of movement, implementing discontinuous grinding. The distinctive features of such grinding are decreasing the heat release rate in a contact zone; ensuring intermittence of the process with a solid grinding wheel; reverse grinding; cutting by different edges of an abrasive grain; stabilization of working parameters of a grinding wheel; ensuring work of a grinding wheel in a self-sharpening mode. The design of the planetary grinding tool was developed for plane surface processing for implementation of the specified distinctive features of planetary grinding. The kinematics of shaping a surface by flat face diamond grinding has been investigated; manufacturing capabilities of planetary face grinding have been revealed, and ways of improvement of quality and productivity have been offered. The algorithm and the program to define the motion path of a grain depending on the given set of grinding factors were received. Optimization of the process of face diamond grinding using the planetary grinding device has been confirmed with the developed program and techniques to choose cutting conditions of planetary grinding and characteristics of grinding wheels for processing different materials. While studying the process of planetary grinding, special attention was paid to the research how processing conditions influence microgeometry of the processed surface made of steel 4X5M (Russian State Standard (GOST)). As a result of the executed research, it was established that surface roughness parameter Ra during the processing using the planetary grinding device is 35 - 40% less than when using the tool with the solid cutting surface. This phenomenon can be accounted for more uniform work of the cutting grains of the planetary grinding tool as the number of meetings of diamond grains with the surface being processed increases. At the same time, it should be noted that during the planetary grinding more intensive smoothing of tops of microroughnesses is observed that provides the creation of steadier cutting shape. The given method of calculation of cost value of grinding operation allows solving various manufacturing problems: to compare cost value of grinding different materials, grinding wheels of different parameters; to define the optimum grinding conditions.

Laser cutting: influence on morphological and physicochemical properties of polyhydroxybutyrate.

PubMed

Lootz, D; Behrend, D; Kramer, S; Freier, T; Haubold, A; Benkiesser, G; Schmitz, K P; Becher, B

2001-09-01

Polyhydroxybutyrate (PHB) is a biocompatible and resorbable implant material. For these reasons, it has been used for the fabrication of temporary stents, bone plates, nails and screws (Peng et al. Biomaterials 1996;17:685). In some cases, the brittle mechanical properties of PHB homopolymer limit its application. A typical plasticizer, triethylcitrate (TEC), was used to overcome such limitations by making the material more pliable. In the past few years, CO2-laser cutting of PHB was used in the manufacturing of small medical devices such as stents. Embrittlement of plasticized PHB tubes has been observed, after laser machining. Consequently, the physicochemical and morphological properties of laser-processed surfaces and cut edges of plasticized polymer samples were examined to determine the extent of changes in polymer properties as a result of laser machining. These studies included determination of the depth of the laser-induced heat affected zone by polariscopy of thin polymer sections. Molecular weight changes and changes in the TEC content as a function of distance from the laser-cut edge were determined. In a preliminary test, the cellular response to the processed material was investigated by cell culture study of L929 mouse fibroblasts on laser-machined surfaces. The heat-affected zone was readily classified into four different regions with a total depth of about 60 to 100 microm (Klamp, Master Thesis, University of Rostock, 1998). These results correspond well with the chemical analysis and molecular weight measurements. Furthermore, it was found that cells grew preferentially on the laser-machined area. These findings have significant implications for the manufacture of medical implants from PHB by laser machining.

Kirkwood Community College: A Leader in Turbulent Times

ERIC Educational Resources Information Center

Root, Cynthia

2005-01-01

With its global vision, community partners and cutting edge curriculum, Kirkwood Community College has become a leader in emergency preparedness and response training. The college is integrally involved with a variety of training consortia and entities including HMTRI (Hazardous Materials Training Research Institute), PETE (Partnership for…

Investigation of pathogen infiltration into produce using Xradia Bio MicroCT

USDA-ARS?s Scientific Manuscript database

The internalization of human pathogens into plant tissues has received significant attention. Human pathogens can infiltrate plant tissue through stomata, cut edges, wounds on produce, or the plant vascular system. The nondestructive X-ray computed microtomography (MicroCT) technique is an X-ra...