Removal Of Excess Material Research Articles

Slurry-based additive manufacturing of ceramic parts by selective laser burn-out

Abstract This study proposes a novel process of slurry-based additive manufacturing of ceramic parts by selective laser burn-out (SLB). The process employs the slurry layer to replace the sheet material used in the process of laminated object manufacturing (LOM) and computer-aided manufacturing of laminated engineering materials (CAM-LEM). A part of binder and solution in the fresh slurry layer permeated into the dried green layers to achieve a good binding strength; then the green part was build with laser irradiation to burn out binder. Two scanning modes were used; the outline scanning traced out the outline of the predefined part slice geometry, and cutting scanning facilitated removal of excess material. Consequently, the new process benefits the fabrication of the large parts as LOM and CAM-LEM possessing. Many accessory facilities used in LOM and CAM-LEM are not required. The feasibility of the new process is verified through the fabrication of the alumina parts.

The effect of throat underflushing on the fatigue strength of fillet weldments

ABSTRACTThe paper deals with the effect of the weld bead geometry on the fatigue strength of a joint, mainly focusing on geometry change due to post‐weld grinding. The weld toe burr grinding usually has a positive effect on the fatigue strength; however, excessive material removal at the weld throat can decrease its strength. This effect was experimentally evaluated and compared with proper numerical estimations. By means of the numerical evaluations of the effective stress, obtained by the implicit gradient method, the estimation of the geometric component of the grinding process is possible. With this procedure, it is possible to analyse a real joint, geometrically modelled by laser scanner acquisition, and also to assess the excessive net section reduction in a grinding operation.

The measurement of surface roughness to determine the suitability of different methods for stone cleaning

The roughness of stone surface was measured, before and after bead blasting-based cleaning methods, to select the most efficient one to be used in masonry and stonework of specific areas of the Cathedral of Segovia (Spain). These types of cleaning methods can, besides the removal of soiling and surface deposits, leave a rougher surface, which would mean higher and more rapid water retention and deposit accumulation due to a specific surface increase, therefore accelerating stone decay. Or, in contrast, the cleaning method can be so aggressive that it can smooth the surface by reducing its roughness, a fact that usually corresponds to excessive material removal—soot and deposits–-but also part of the stone substrate. Roughness results were complemented with scanning electron microscopy observations and analyses and colour measurements. Finally, it was possible to select the best cleaning method among the six that were analysed, for different areas and different stone materials. Therefore, this study confirms the measurement of surface roughness as a reliable test to determine the suitability of stone cleaning methods; it is a non-destructive technique, portable and friendly to use, which can help us to rapidly assess—together with other techniques—the efficacy and aggressiveness of the stone cleaning method.

Abstract 5462: Single dose dermal irritation study of apaziquone in rabbits

Abstract Introduction and Objectives: Apaziquone is a novel bioreductive alkylating agent in development for intravesical therapy of nonmuscle invasive bladder cancer (NMIBC). The standard dose of apaziquone in all ongoing clinical studies is 4 mg/ 40 mL (0.1mg/mL). For clinical use, lyophilized apaziquone is reconstituted with diluent and instilled in the bladder. During the preparation and handling of the product, there is a possibility of accidental dermal contact for the healthcare professionals. To date, dermal irritation potential of apaziquone has not been investigated. The purpose of this study was to evaluate the dermal irritation potential of apaziquone in rabbits. Materials & Methods: Apaziquone was administered topically on the skin (non-occlusive) to New Zealand White (NZW) rabbits as a single dose for 4 hours followed by removal of excess material, and skin examination for up to 72 hours after removal of excess material. Each male NZW rabbits (3/group; one group) had three identified treatment sites on the back: (1) untreated (2) vehicle (diluent for apaziquone) and (3) apaziquone (0.1 mg/mL). Animals were treated with a single non-occlusive dermal dose of apaziquone (0.5 mL of 0.1 mg/mL) and vehicle for 4 hours followed by removal of excess material. No test material or vehicle was applied to the site designated as untreated. The treatment sites were observed and scored at baseline and at various times (4, 24, 48, and 72 hours) after removal of excess test article and vehicle. The following parameters were evaluated: viability, clinical observations, and dermal observations/scoring by modified Draize method. Results: No clinical signs of toxicity were observed during the study and no signs of dermal irritation related to test article or vehicle/diluent were observed at any of the dose sites in any of animals. The Primary Dermal Irritation Index for apaziquone, administered at clinically relevant exposures, had a value of zero (0) indicating no irritation at the concentration and for the duration of exposure. Conclusion: Apaziquone did not cause any dermal irritation in rabbits at a clinically relevant concentration. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5462. doi:1538-7445.AM2012-5462

Optimization of Turning Process Parameters for Their Effect on En 8 Material Work piece Hardness by Using Taguchi Parametric Optimization Method

A common method to manufacture parts to a specific dimension involves the removal of excess material by machining operation with the help of cutting tool. Turning process is the one of the methods to remove material from cylindrical and non-cylindrical parts. In this work the relation between change in hardness caused on the material surface due the turning operation with respect to different machining parameters like spindle speed, feed and depth of cut have been investigated. Taguchi method has been used to plan the experiments and EN 8 metal selected as a work piece and coated carbide tool as a tool material in this work and hardness after turning has been measured on Rockwell scale. The obtained experimental data has been analyzed using signal to noise and. The main effects have been calculated and percentage contribution of various process parameters affecting hardness also determined.

Surface substance loss of subsurface bovine enamel lesions after different steps of the resinous infiltration technique: a 3D topography analysis

Surface substance loss of subsurface enamel lesions before (baseline/demineralization) and after each step of the infiltration technique was evaluated by means of a three-dimensional focus variation. Eighty enamel specimens were prepared and partially varnished (control). Non-varnished areas were demineralized (pH 4.95; 28 days), and etched with phosphoric acid gel (20%; 5 s). Specimens were randomly assigned to eight groups (n = 10), and were infiltrated using four resinous materials. In subgroups 1, polymerization and finishing with abrasive polishing strips followed. In subgroups 2, excess material was removed before polymerization (E1/E2-Excite, Vivadent; F1/F2-Fortify, Bisco; G1/G2-Glaze & Bond, DMG; I1/I2-Icon, DMG). Topometrical evaluation revealed a negligible substance loss of demineralized enamel. After etching, mean (±SD) differences of height decreased uniformly (-6.6 ± 2.0 μm; p = 0.089; ANOVA). For infiltrated lesions, DH of subgroups 1 was comparable to the etched lesions, with a significant increase (compared to etched lesions) in subgroups 2 (1.1 ± 0.1 μm; p < 0.001; t test). Within the limitations of this study, it is concluded that etching of initial subsurface lesions will result in significant surface substance loss; removal of excess material before light-curing should simplify the infiltration procedure, and this will avoid any abrasion resulting from polishing procedures.

Small Bowel Obstruction Associated With Use of a Gelatin-Thrombin Matrix Sealant (FloSeal) after Laparoscopic Gynecologic Surgery

We report 2 cases of laparoscopic gynecologic procedures, complicated by small bowel obstruction possibly related to use of a hemostatic agent. The cause was most likely from excess material not incorporated in the hemostatic clot at the site of application. Gentle irrigation and removal of excess material from the site of application is recommended by the manufacturer of FloSeal and may reduce the risk of postoperative adhesion formation and small bowel obstruction.

Study on the planarization behaviour of copper CMP utilizing a dense pattern and a global step

AbstractThe major aim of CMP is not the removal of excess material but the planarization of the surface. Therefore the determination of the planarization length appears to be more important than the removal rate itself. It has been shown, that the planarization length is not a constant process parameter, but is related to the removal respectively to the polish time in a square root behaviour. Founded on models proposed by Boning, Ouma, et. al. we applied a sequential polish on a single quasi infinite step. The resulting profile could be simulated by a sequential convolution of the surface contour with a Gaussian transfer function.To come closer to the situation on a chip pattern we investigated the planarization behaviour on a specific pattern of the MIT854AZ copper CMP test chip, where a large area of unpatterned surface touches a pattern with a specific constant density.The 200 mm wafer samples consisted of RIE structured oxide films covered with 850 nm ECD copper. The polish was performed on a standard semiconductor manufacturing tool, using a commercial consumables set. The surface profiles were determined by a high resolution profiler within the polishing sequence. The densely patterned areas are removed within a certain polishing time while the transition point between the unpatterned and patterned area appears as a global step. The deposited copper thickness is sufficient to study the contour evolution in both phases, before and after removal of the dense pattern. The paper presents the experimental results on the contour evolution for the patterned fields as well as the global step.

Economic considerations in die-form compensation for nett-forming

Engineering components which operate in aggressive environments are invariably manufactured from high-strength, thermally resistant materials. Such materials are difficult to subject to machining, subsequent to the forming operation, with a view to achieving the assemblable form of the component. Further, in circumstances where the geometry of the component is complex, the option of machining the formed component to achieve the assemblable form would be prohibitively expensive. In such circumstances, the aim would be to achieve the nett-form of the functional surfaces of the component in the primary forming operation. A prime consideration in developing the nett-form of the component is the cost of iterative manufacturing trials required to achieve sufficient understanding of the die-form changes which are necessary for nett-forming of engineering components. It is conceivable that an industry operates with a sufficiently small family of components to enable the application of the derived die-compensation procedures for individual products across the entire family. A further consideration in attempting to nett-form the functional surfaces is the cost of fixturing a near-nett-form of the component to enable the removal of excess material. It is recognised that the smaller the amount of excess material, the greater the cost of fixturing the component for machining operations. Technical factors which influence the cost of designing tools for nett-forming refer to the knowledge required for performing physical modelling (PM) trials to derive the pressure contour on the nominal die-cavity, the tri-axial force transducer technology, the capacity for manufacturing tools of a larger scale to support PM experiments, knowledge of the elastic analysis of die-behaviour using finite element techniques and knowledge of die-form compensation algorithms. It would follow that most industries which expect to effect die-form compensation with a view to the nett-forming of engineering components would have to purchase some of the services from specialist laboratories.

Organically Deposited Metallic Films for Device Fabrication

ABSTRACTAdvances in integrated circuit density, speed and complexity are dependent on lower resistance, finer line width on-chip interconnections. Methods for incorporating copper interconnects into IC fabrication processes have been developed which accomplish this objective but most of these methods use some form of blanket metal deposition that requires mechanical and/or chemical removal of excess material. To date, investigations into the selective deposition of conductor materials for device fabrication have met with limited success. A new process for selectively depositing metallic conductors using inexpensive, organic-based chemical solutions could potentially force a paradigm shift in the deposition of metals for microelectronic applications. Reversing the process currently used for selectively removing impurities from metal bearing waste streams, electrochemically controlled deposition of metals from electrically non-conducting organic solutions on submicron feature sizes is possible. A description of the fundamental electrochemical processes involved and parameter space available to engineer the solution chemistry will be presented along with experimental results from model systems. A discussion of the technology in light of ULSI issues and applications will be included.

Studies of Sewage Purification: XV. Effective Bacteria in Purification by Trickling Filters

In studies of the activated sludge process of sewage purification, it was shown-1, that the predominant bacteria in activated sludge belonged to a group represented by zoogleal formations. Subsequently it was demonstrated 2 that these bacteria are the active agents in activated sludge, being capable in pure culture of producing not only activated sludge but also possessing the powers of oxidation and purification in herent to natural activated sludge. In the trickling filter process of sewage purification, also biological in nature, the fundamental set-up of the process would suggest that the active agents might be the same organisms as those of activated sludge. That is, with both processes the success of the purification depends on the presence of three essential elements, (1) bacterial masses or floes, (2) food supply for these bacteria, i.e. polluting material, and (3) a con tinuous source of oxygen. The process is also dependent upon a phys ical means of keeping these three elements dispersed and continuously in contact with each other. In the activated sludge process the contact and mixing is brought about by an agitation of the sludge-sewage mix with compressed air which also provides a continuous source of oxygen. In the trickling filter the sludge mass is held dispersed on a framework of stones, or other material, while the sewage trickles over the surfaces of the sludge. The interstices of this framework provide an ample air reservoir and the circulation of this contained oxygen is aided, in part, by the flow of liquid through the system. intermittent flow, time is provided for the sludge to utilize the adsorbed substances. Moreover, the successful perpetuation of both processes is dependent on the fre quent or continuous removal of excess and, frequently, detrimental by products. Soluble fractions of such by-products are removed with the effluent in both processes. Suspended matter is removed continuously in the activated sludge process by the withdrawal of excess sludge while in the trickling filter such withdrawals are accomplished by a continuous but moderate unloading and by a periodic sloughing off of the accumula tions on the filter stones. With both processes the removal of excess material is aided probably by successive growths of various biological forms. The latter factor is probably more significant in the trickling filter where such biological growths are more varied and more abundant. 639