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Diamond-like carbon films with Ti dopant (Ti-DLC) are synthesized by reactive magnetron sputtering using a pure Ti metal target. This study determines the effect of methane flow ratios (Rm=CH4/(Ar + CH4), ranging from 4 to 12%) on the surface morphology, microstructure, mechanical properties, and cermet cutting tool insert features of Ti-DLC films. The GIXRD diffraction spectrum for Ti-DLC film depicts an amorphous structure. There are peaks for nano-crystalline TiC at 2θ values of 35.88°, 41.52°, and 60.14°, which respectively correspond to the (111), (200), and (220) planes of the face-centered cubic structure. The characteristic binding energy of C 1s, Ti 2p, and O 1s for Ti-DLC film is determined using a high-resolution XPS spectrum. Increasing Rm flow ratio (reducing Ti metal doping) increases the intensity of the Raman spectrum because there is an increased sp2-C (sp2/sp3 ratio) site fraction for DLC components. The experimental results show that the hardness of the DLC film increases from 11.07 to 14.76 GPa as the Rm flow ratio is increased from 4 to 12%. The adhesive strength of the Ti-DLC film coating is measured using a scratch test and shows that the film adheres well to the substrate. The Ti-DLC films are coated onto cutter inserts for the dry milling of an Inconel 718 workpiece, and the results show that all coated tools have a significantly longer tool life than uncoated tools. [ABSTRACT FROM AUTHOR]

The performance of Ti films coated on SUS 304 stainless steel and soda-lime glass using direct current (DC) sputtering has been analyzed in this study. The quality characteristics of the films were examined by means of Taguchi design, with an orthogonal array, signal-to-noise (S/N) ratio and analysis of variance (ANOVA). Progressive loading was used to induce failure in the Ti film with scratch adhesion critical loads LC1 and LC2 on the substrate surface. The X-ray diffraction spectrum of the Ti-coated films depict hexagonal close-packed (HCP) structural with (100), (002) and (101). The analysis of S/N ratios, grey Taguchi and ANOVA for multiple quality performance shows that the contribution of DC power and deposition time to the multiple quality characteristics is 79.21% and 11.04% respectively. In the confirmation study, based on the grey Taguchi design system, the rate of improvement is 10.34% in coefficient of friction, 17.84% in corrosion potential, 10.15% in micro-hardness, and 5.99% in elastic recovery, respectively. [ABSTRACT FROM AUTHOR]

Amorphous TiO2 films were deposited on non-alkali glass by reactive radio-frequency magnetron sputtering using a TiO2 ceramic target. This study analyzed the effects of Ar/O2/N2 gas flow ratios, deposition time, and thermal annealing treatments on the morphological and structural phases and photocatalytic characteristics of the TiO2 films. The XRD results showed a broad hump shape, indicating the existence of an amorphous phase characteristic of TiO2 films. For O2/N2 co-doped TiO2 films, as the O2 and N2 concentration increased, higher photocatalytic activity of TiO2 materials was obtained, while the film growth rate and band gap energy (Eg) values tended to decrease. When increasing the TiO2 film thickness, the amorphous phases remained unchanged, the Eg value narrowed, and higher photocatalytic activity was obtained. After thermal annealing treatments, the TiO2 films showed ultra-hydrophilicity and outstanding photocatalytic efficiency. The TiO2 film annealed at 450°C displayed higher photocatalytic performance and improved mechanical properties. It was seen that when using a higher nanoindentation load, higher hardness (H) and elastic modulus (E) were obtained, but the H/E, H3/E2, and elastic recovery rate (%Re) did not change significantly. [ABSTRACT FROM AUTHOR]

Multi-element alloy doped diamond-like carbon (DLC) films were coated using sputtering with a (AlCrNbSiTiV) target. TEM and XRD results indicated DLC film had an amorphous compound feature incorporating polycrystalline phases around the face-centered cubic structure, which were embedded into the amorphous carbon matrix. The Raman spectra and mechanical characteristics of the DLC film sample were associated with concentration changes in the carbon and the multi-element alloy doped in the DLC films, which depended on the DC power. This investigation indicated that improved mechanical properties, including hardness and the elastic recovery rate, can be obtained from the multi-element alloy doped DLC film coated with proper DC sputtering power. These results demonstrated a proper DC power modifies the structure of multi-element alloy doped DLC film and improves its mechanical performance. This study should pave the way for the development of DLC film and elevate its application in various industries. [ABSTRACT FROM AUTHOR]

The 5G wireless technology is recently standardized for meeting intense demand. The Long Term Evolution (LTE) technology provides an easy, time-saving, and low-cost method for deploying a 4G/5G network infrastructure. To support multimedia service and higher bandwidth data delivery, an LTE MAC layer has Quality of Service (QoS) support with several QoS class indicator (QCI) levels. Based on LTE current QCI priority and QoS requirements in UEs, the original Max-Rate scheduler, Proportionally Fair (PF) and Modified Largest Weighted Delay First (M-LWDF) algorithms could not achieve their goal owing to the UE's dynamic physical capacity with a different Channel Quality Indicator (CQI) at run time. For better QoS service than LTE networks, per UE's CQI state for each resource block (RB) must be considered simultaneously in LTE MAC layer resource allocation with cross-layer support. As downlink real estimated capacity is dynamic owing to a UE's periodic CQI reporting, the CQI state in LTE scheduling must be considered. This study proposes a smart and flexible scheme for Enhanced Utilization Resource Allocation (EURA) including three novel mechanisms that can dynamically fit UEs' CQI states. The simulation results in this study demonstrate that the proposed EURA scheme outperforms the contrast schemes (Max-Rate, EXP/PF and M-LWDF), can save more rare radio capacity, and improve the utilization of radio resource assignment. [ABSTRACT FROM AUTHOR]

This study fabricates a roughing electrode of electrical discharge machining (EDM) using a rapid prototyping (RP) system and investment casting technology, which reduces the overall time that is required for fabrication and the cost of the manufacturing process for a selected electrode. Pro/E (3D CAD) software is used to design the electrode prototype, which has a complex appearance, and to transform the CAD model into stereolithography (STL) format. An RP machine (Zcorp 402 3DP) is used to construct a gypsum-based powder model. After a sealing process using the permeation of resin, the water resistance and strength of the gypsum-based material are increased. The manufacturing process then involves creating a wax model with a gypsum electrode that is strengthened by resin permeation by casting a vulcanized silicone molding. The brass electrode is fabricated using investment casting technology. The results of an EDM test show that the brass electrodes with RP that are manufactured perform well and the total time that is required to machine the EDM electrode using RP is 15.8% less than the time that is required for a CNC machining process. [ABSTRACT FROM AUTHOR]

Coatings are used to increase the surface quality of cutting tools, metal forming stamping, punching tool, plastic injection molding, sliding engine components for automobiles or decorative applications. Many parameters affect the manufacturing performance. Chromium nitride is frequently used for metal forming, plastic molding, medical implants and cutting tools because it has a low coefficient of friction, high hardness and good thermal stability. Optimizing multiattribute characteristics (MACs) requires experience but is crucial to the manufacturing process. This study uses a combination of entropy and range of value methods to optimize MACs to minimize surface roughness (E1), flank wear (E2) and hardness (E3) for CrWN hard film tools that are used for turning AISI 304 stainless steel. And the results are compared with those for grey relational analysis (GRA). The L9 Taguchi experimental data are used to rank the coating configurations (alternatives) for each experimental test, and a decision matrix is initially defined. The results show that flank wear (E2) has the greatest effect on the outputs. Combination F9 (A3B3C2D1) ranks highest of the coating configurations and the value is the same as that which is calculated using GRA. The proposed method features a relatively simple computational procedure and can be easily used by a technicians or engineers to optimize MACs for real manufacturing practices and environments. [ABSTRACT FROM AUTHOR]

This paper seeks to improve the surface quality of electrical discharge machining (EDM) Ti-6Al-4V using plasma etching treatment and TiN coating. The EDM parameter setting is optimized firstly based on grey-Taguchi method. Four EDM parameters, including current (A), voltage (V), pulse duration (μs), and duty factor (%), are selected for multiple performance of lower electrode wear rate (EWR), higher material removal rate (MRR), and better surface roughness (SR). An orthogonal array, signal-to-noise (S/N) ratios, and analysis of variance (ANOVA) are used to analyze the effects of these EDM parameters. Normality tests show that all the distributions fit normality assumption with p = 0.276, 0.688, and 0.663, respectively. The EDM process is stable over time monitored by Shewhart control charts. It is observed that there is an EDM damaged layer on the surface consisting of debris, microcracks, molten drops, and solidified metals by scanning electron microscopy. The plasma etching and TiN coating are employed to improve surface quality of the EDMed Ti-6Al-4V alloys. The results demonstrate that using the oxygen plasma etching treatment, the damaged phenomena are decreased, and the mean SR value is reduced from Ra = 2.91 to Ra = 2.50 μm. In addition, when the plasma-treated alloy is coated with Ti buffer/TiN coating by physical vapor deposition, the surface morphology exhibits less defects and a better surface finish. The mean SR values are further reduced from Ra = 2.50 μm to Ra = 1.48 μm (for 740 nm TiN film) and Ra = 0.61 μm (for 1450 nm TiN film), respectively. [ABSTRACT FROM AUTHOR]

This work presents an amino plasma-enhanced chemical vapour deposition (NH3 PECVD) treatment to modify multiwall carbon nanotubes (MWCNTs) for the immobilization of antibodies (IgG-gold), and the effects of treatment time were studied. A titanium nitride (TiN) buffer layer and a nickel catalyst layer were deposited on silicon substrates for synthesis of MWCNTs using thermal CVD. The MWCNTs were modified by amine (NH2−) or amino (NH−) functional groups for 1, 3, and 5 min by PECVD, respectively. Mouse IgG-golds were immobilized on the modified MWCNTs using glutaraldehyde (GA) as a crosslinker. The performance of the modified MWCNTs was characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), Fourier transform infrared spectroscopy (FT-IR), contact angle system (CA), X-ray photoelectron spectroscopy (XPS, ESCA), and UV-visible spectroscopy. Results show that the efficiency of IgG-gold immobilization was increased with the increase of NH3 PECVD treatment time. The NH3 PECVD treatment changed the surface properties of the MWCNTs, tuning them more hydrophilic without affecting their structure. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1343-1351, 2016. [ABSTRACT FROM AUTHOR]

Background: Robot-based joint-testing systems (RJTS) can be used to perform unconstrained laxity tests, measuring the stiffness of a degree of freedom (DOF) of the joint at a fixed flexion angle while allowing the other DOFs unconstrained movement. Previous studies using the force-position hybrid (FPH) control method proposed by Fujie et al. (J Biomech Eng 115(3):211-7, 1993) focused on anterior/posterior tests. Its convergence and applicability on other clinically relevant DOFs such as valgus/varus have not been demonstrated. The current s1tudy aimed to develop a 6-DOF RJTS using an industrial robot, to propose two new force-position hybrid control methods, and to evaluate the performance of the methods and FPH in controlling the RJTS for anterior/posterior and valgus/varus laxity tests of the knee joint.Methods: An RJTS was developed using an industrial 6-DOF robot with a 6-component load-cell attached at the effector. The performances of FPH and two new control methods, namely force-position alternate control (FPA) and force-position hybrid control with force-moment control (FPHFM), for unconstrained anterior/posterior and valgus/varus laxity tests were evaluated and compared with traditional constrained tests (CT) in terms of the number of control iterations, total time and the constraining forces and moments.Results: As opposed to CT, the other three control methods successfully reduced the constraining forces and moments for both anterior/posterior and valgus/varus tests, FPHFM being the best followed in order by FPA and FPH. FPHFM had root-mean-squared constraining forces and moments of less than 2.2 N and 0.09 Nm, respectively at 0° flexion, and 2.3 N and 0.14 Nm at 30° flexion. The corresponding values for FPH were 8.5 N and 0.33 Nm, and 11.5 N and 0.45 Nm, respectively. Given the same control parameters including the compliance matrix, FPHFM and FPA reduced the constraining loads of FPH at the expense of additional control iterations, and thus increased total time, FPA taking about 10 % longer than FPHFM.Conclusions: The FPHFM would be the best choice among the methods considered when longer total time is acceptable in the intended clinical applications. The current results will be useful for selecting a force-position hybrid control method for unconstrained laxity tests using an RJTS. [ABSTRACT FROM AUTHOR]

The purpose of this study was to measure the long-term growth of the mandible in miniature pigs using 3D Cone-Beam Computerized Tomography (CBCT). The mandibles of the pigs were scanned monthly over 12 months using CBCT and the 3D mandibular models were reconstructed from the data. Seventeen anatomical landmarks were identified and classified into four groups of line segments, namely anteroposterior, superoinferior, mediolateral and anteroinferior. The inter-marker distances, inter-segmental angles, volume, monthly distance changes and percentage of changes were calculated to describe mandibular growth. The total changes of inter-marker distances were normalized to the initial values. All inter-marker distances increased over time, with the greatest mean normalized total changes in the superoinferior and anteroposterior groups (p<0.05). Monthly distance changes were greatest during the first four months and then reduced over time. Percentages of inter-marker distance changes were similar among the groups, reaching half of the overall growth around the 4th month. The mandibular volume growth increased non-linearly with time, accelerating during the first five months and slowing during the remaining months. The growth of the mandible was found to be anisotropic and non-homogeneous within the bone and non-linear over time, with faster growth in the ramus than in the body. These growth patterns appeared to be related to the development of the dentition, providing necessary space for the teeth to grow upward for occlusion and for the posterior teeth to erupt. [ABSTRACT FROM AUTHOR]

Background: Predictions of the forces transmitted by the redundant force-bearing structures in the knee are often performed using optimization methods considering only moment equipollence as a result of simplified knee modeling without ligament contributions. The current study aimed to investigate the influence of model complexity (with or without ligaments), problem formulation (moment equipollence with or without force equipollence) and optimization criteria on the prediction of the forces transmitted by the force-bearing structures in the knee. Methods: Ten healthy young male adults walked in a gait laboratory while their kinematic and ground reaction forces were measured simultaneously. A validated 3D musculoskeletal model of the locomotor system with a knee model that included muscles, ligaments and articular surfaces was used to calculate the joint resultant forces and moments, and subsequently the forces transmitted in the considered force-bearing structures via optimization methods. Three problem formulations with eight optimization criteria were evaluated. Results: Among the three problem formulations, simultaneous consideration of moment and force equipollence for the knee model with ligaments and articular contacts predicted contact forces (first peak: 3.3-3.5 BW; second peak: 3.2-4.2 BW; swing: 0.3 BW) that were closest to previously reported theoretical values (2.0-4.0 BW) and in vivo data telemetered from older adults with total knee replacements (about 2.8 BW during stance; 0.5 BW during swing). Simultaneous consideration of moment and force equipollence also predicted more physiological ligament forces (< 1.0 BW), which appeared to be independent of the objective functions used. Without considering force equipollence, the calculated contact forces varied from 1.0 to 4.5 BW and were as large as 2.5 BW during swing phase; the calculated ACL forces ranged from 1 BW to 3.7 BW, and those of the PCL from 3 BWto 7 BW. Conclusions: Model complexity and problem formulation affect the prediction of the forces transmitted by the force-bearing structures at the knee during normal level walking. Inclusion of the ligaments in a knee model enables the simultaneous consideration of equations of force and moment equipollence, which is required for accurately estimating the contact and ligament forces, and is more critical than the adopted optimization criteria. [ABSTRACT FROM AUTHOR]

A pilot-scale field study was carried out to investigate the distribution of Hg and other selected elements (i.e., As, B, and Se), i.e., emission to ambient air, uptake by surface vegetation, and/or rainfall infiltration, after flue gas desulfurization (FGD) material is applied to soil. Three FGD materials collected from two power plants were used. Our results show Hg released into the air and uptake in grass from all FGD material-treated soils were all higher (P < 0.1) than the amounts observed from untreated soil. Hg in the soil amended with the FGD material collected from a natural oxidation wet scrubber (i.e., SNO) was more readily released to air compared to the other two FGD materials collected from the synthetic gypsum dewatering vacuum belt (i.e., AFO-gypsum) and the waste water treatment plant (i.e., AFO-CPS) of a forced oxidation FGD system. No Hg was detected in the leachates collected during the only 3-hour, 1-inch rainfall event that occurred throughout the 4-week testing period. For every kilogram of FGD material applied to soil, AFO-CPS released the highest amount of Hg, B, and Se, followed by SNO, and AFO gypsum. Based on the same energy production rate, the land application of SNO FGD material from Plant S released higher amounts of Hg and B into ambient air and/or grass than the amounts released when AFO-gypsum from Plant A was used. Using FGD material with lower concentration levels of Hg and other elements of concern does not necessary post a lower environmental risk. In addition, this study demonstrates that considering only the amounts of trace elements uptake in surface vegetation may under estimate the overall release of the trace elements from FGD material-amended soils. It also shows, under the same soil amendment conditions, the mobility of trace elements varies when FGD materials produced from different processes are used. [ABSTRACT FROM PUBLISHER]

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Abstract: Efforts are made to explore the hysteresis characteristics of vortex shedding in a pipe flow, whose velocity varies periodically in time. Results obtained show that during acceleration of the flow, the vortex strength tends to be stronger, whereas during deceleration of the flow, the situation is reversed. As reconstructed from the velocity signals measured at a point in the flow field, the shed vortex arrays appear to possess uneven vortex strengths in response to periodically-varying incoming flows. Furthermore, in the hysteresis range, the streamwise spacings between the vortices appear to be unequal. [Copyright &y& Elsevier]

Background: Predictions of the forces transmitted by the redundant force-bearing structures in the knee are often performed using optimization methods considering only moment equipollence as a result of simplified knee modeling without ligament contributions. The current study aimed to investigate the influence of model complexity (with or without ligaments), problem formulation (moment equipollence with or without force equipollence) and optimization criteria on the prediction of the forces transmitted by the force-bearing structures in the knee.Methods: Ten healthy young male adults walked in a gait laboratory while their kinematic and ground reaction forces were measured simultaneously. A validated 3D musculoskeletal model of the locomotor system with a knee model that included muscles, ligaments and articular surfaces was used to calculate the joint resultant forces and moments, and subsequently the forces transmitted in the considered force-bearing structures via optimization methods. Three problem formulations with eight optimization criteria were evaluated.Results: Among the three problem formulations, simultaneous consideration of moment and force equipollence for the knee model with ligaments and articular contacts predicted contact forces (first peak: 3.3-3.5 BW; second peak: 3.2-4.2 BW; swing: 0.3 BW) that were closest to previously reported theoretical values (2.0-4.0 BW) and in vivo data telemetered from older adults with total knee replacements (about 2.8 BW during stance; 0.5 BW during swing). Simultaneous consideration of moment and force equipollence also predicted more physiological ligament forces (< 1.0 BW), which appeared to be independent of the objective functions used. Without considering force equipollence, the calculated contact forces varied from 1.0 to 4.5 BW and were as large as 2.5 BW during swing phase; the calculated ACL forces ranged from 1 BW to 3.7 BW, and those of the PCL from 3 BW to 7 BW.Conclusions: Model complexity and problem formulation affect the prediction of the forces transmitted by the force-bearing structures at the knee during normal level walking. Inclusion of the ligaments in a knee model enables the simultaneous consideration of equations of force and moment equipollence, which is required for accurately estimating the contact and ligament forces, and is more critical than the adopted optimization criteria. [ABSTRACT FROM AUTHOR]

Background: Total hip replacement (THR) is considered to be the most effective treatment option for advanced osteoarthritis of the hip in large breed dogs. However, a proportion of post-THR patients suffer prosthesis dislocation for various reasons, which may be addressed by a constrained acetabular prosthesis design. The study proposed a new THR with constrained acetabular component that aimed to decrease the incidence of postoperative dislocation while maintaining the necessary range of motion (ROM); and, through computer-simulated implantations, evaluated the ROM of the THR with and without malpositioning of the acetabular component.Methods: A new THR with a constrained acetabular component that had an inward eccentric lining and a 60° cut-out on the dorsal side was designed, and its computer-aided design models were implanted into the pelvic and femoral models reconstructed from the computed tomography data of six healthy Labrador Retriever dogs. The allowable and functional ROM of the implanted THR were determined via computer simulations. The contact patterns between the bone or the prosthetic components at extreme positions of the THR were analyzed. Influence of malpositioning of the acetabular component on the ROM was assessed.Results: The means (SD) of the functional ranges for flexion, extension, adduction, abduction, internal rotation and external rotation were 51.8° (6.6°), 163.3° (7.3°), 33.5° (5.7°), 74.0° (3.7°), 41.5° (8.3°) and 65.2° (9.9°), respectively. Malpositioning of the acetabular component by 20° in one direction was found to reduce ROM in other directions (reducing lateral opening: flexion: 12°, adduction: 20°, internal/external rotations: < 20°; increasing lateral opening: extension and abduction: < 16°; reducing retroversion: extension: < 20°, abduction: 15°, external rotation: < 20°; increasing retroversion: flexion: < 20°, abduction, adduction and internal rotation: 20°).Conclusions: From the computer-aided surgical simulations, the new THR was found to have sufficient functional ranges for flexion, extension, abduction, adduction and external rotation for Labrador Retrievers. Analysis of the malpositioning of the acetabular component suggests that accurate placement of the acetabular component is critical for achieving desirable ROM for daily activities. [ABSTRACT FROM AUTHOR]