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A chipping study was conducted during the winter of 2015 in Berks County, Pennsylvania, to determine efficacy against field collected egg masses of the spotted lanternfly, Lycorma delicatula (White) (Hemiptera: Fulgoridae). Infested Ailanthus altissima Swingle (Sapindales: Simaroubaceae) trees in eastern Pennsylvania were felled and egg masses were counted. Sections were either chipped or allowed to remain intact as controls. Chipped material and intact wood controls were placed in screened barrels and monitored for emergence. No L. delicatula nymphs were found in the chipped treatment, as opposed to hundreds of nymphs per barrel in the intact control treatment. We conclude that mid-winter chipping, using the standard 1-inch in 2-dimension chip size, is a quarantine safe mitigation method suitable for treating wood infested with L. delicatula egg masses. [ABSTRACT FROM AUTHOR]

Objective The objective of this 5-year cohort investigation was to determine the survival and success rate of all-ceramic reconstructions on zirconia oral implants. Material and Methods Ninety-three patients received 122 one-piece zirconia implants. One hundred seventeen implants were restored with 63 single crowns ( SCs) and 27 three-unit bridges (fixed dental prostheses, FDPs) fabricated using zirconia frameworks ( Procera® Zirconia, Nobel Biocare®, Göteborg, Sweden) hand-layered with a silicate ceramic ( Nobel Rondo™ Zirconia, Nobel Biocare®). With any occurrence of chipping regarded as an event, Kaplan- Meier success curves were plotted. Covariates (gender, location, manufacturing date) were estimated by the use of log-rank tests. Results Eighty-nine patients received prosthetic reconstructions. Sixty-three of them were seen at the 5-year follow-up, with a mean observation time of 58.2 months (47 patients with SCs, 16 patients with FDPs). Reasons for the decreasing number of patients at the follow-up sessions included dropouts due to implant loss ( n = 21), moving ( n = 3), missed appointments ( n = 1), and severe illness ( n = 1). Over half of the SCs (57.2%) and 38% of the FDPs were successful after an observation time of 5 years (overall success rate of 51.7%). The performed log-rank tests revealed no statistically significant differences for the success curves regarding the above-mentioned covariates. Among the 63 restorations that completed the study, 11 of 47 SCs and one of 16 FDPs had to be replaced due to the severity of the observed chipping. This results in survival rates of 76.6% for the SCs and 93.8% for the FDPs. No framework fractures or decementations were observed in any group. Conclusion Hand-layering of zirconia-based SCs and FDPs with Nobel Rondo™ Zirconia restoring one-piece zirconia implants did not show acceptable survival and success rates. Meanwhile, the material has been recalled from the market. It is advised that new materials should undergo adequate preclinical evaluation before coming to the market. [ABSTRACT FROM AUTHOR]

Objectives A recent 3-year randomized controlled trial (RCT) of tooth supported three- to five-unit zirconia–ceramic and metal–ceramic posterior fixed dental prostheses (FDPs) revealed that veneer chipping and fracture in zirconia–ceramic systems occurred more frequently than those in metal–ceramic systems [1] . This study seeks to elucidate the underlying mechanisms responsible for the fracture phenomena observed in this RCT using a descriptive fractographic analysis. Methods Vinyl-polysiloxane impressions of 12 zirconia–ceramic and 6 metal–ceramic FDPs with veneer fractures were taken from the patients at the end of a mean observation of 40.3 ± 2.8 months. Epoxy replicas were produced from these impressions [1] . All replicas were gold coated, and inspected under the optical microscope and scanning electron microscope (SEM) for descriptive fractography. Results Among the 12 zirconia–ceramic FDPs, 2 had small chippings, 9 had large chippings, and 1 exhibited delamination. Out of 6 metal–ceramic FDPs, 5 had small chippings and 1 had large chipping. Descriptive fractographic analysis based on SEM observations revealed that fracture initiated from the wear facet at the occlusal surface in all cases, irrespective of the type of restoration. Significance Zirconia–ceramic and metal–ceramic FDPs all fractured from microcracks that emanated from occlusal wear facets. The relatively low fracture toughness and high residual tensile stress in porcelain veneer of zirconia restorations may contribute to the higher chipping rate and larger chip size in zirconia–ceramic FDPs relative to their metal–ceramic counterparts. The low veneer/core interfacial fracture energy of porcelain-veneered zirconia may result in the occurrence of delamination in zirconia–ceramic FDPs. [ABSTRACT FROM AUTHOR]

This study investigated the adhesion between zirconia framework and four veneering ceramic (VC) materials with varying coefficients of thermal expansions (CTE). Zirconia rods (N = 40) (ICE Zirkon) (diameter: 4 mm, height: 20 mm) were milled and sintered. After firing, the zirconia rods were air-abraded and cleaned. They were randomly assigned to receive four VCs (n = 10/group), namely (a) Vita VM9 (VZ; 9–9.2 × 10−6  K−1), (b) Cerabien ZR (CZ; 9.1 × 10−6K−1), (c) Matchmaker ZR (MM; 9.4 × 10−6 K−1), and (d) Ice Zirconia Ceramic (IZ; 9.6 × 10−6 K−1). The VCs were then fired onto zirconia rods (height: 2 mm, thickness: 2 mm) circumferentially and were thermocycled for 6000 times (5/55 °C, dwell time: 30 s). Specimens were loaded from the top of the zirconia rods (0.5 mm/min) in a universal testing machine until debonding. Shell–Nielsen bond strength values were calculated (MPa). Failure types were evaluated under SEM. The data were statistically analyzed (one-way ANOVA, Tukey’s;α = 0.05). Weibull distribution values including the Weibull modulus (m) (0.05) was calculated. The highest mean bond strength (MPa) was obtained for CZ (42.08 ± 4.08), followed by VZ (41.77 ± 4.92), MM (40.7 ± 3.64), and IZ (40.05 ± 5.78). While mean bond strength for VZ, MM, and IZ were not significantly different (p > 0.05), CZ was significantly higher than that of IZ (p < 0.05). The lowest shape value was for VZ (m = 16.94) and the highest for MM (m = 20.16). Mainly, adhesive failures followed by mixed failures were observed. VCs with a greater mismatch of CTE with the zirconia framework exhibited similar Shell–Nielsen bond strength to those with fewer mismatches. CTE mismatch did not affect the results of CZ (9.1 × 10−6 K−1) and IZ (9.6 × 10−6 K−1). [ABSTRACT FROM AUTHOR]

Objectives Mismatch in thermal expansion coefficient between core and veneering ceramic (Δ α = α core − α veneer , ppm/°C) is reported as a crucial parameter influencing veneer fractures with Yttria-tetragonal-zirconia-polycrystal (Y-TZP) prostheses, which still constitutes a misunderstood problem. However, the common positive Δ α concept remains empirical. The objective of this study is to investigate the Δ α dependence of residual stress profiles in veneering ceramic layered on Y-TZP frameworks. Methods The stress profile was measured with the hole-drilling method in bilayered disc samples of 20 mm diameter with a 0.7 mm thick Y-TZP framework and a 1.5 mm thick veneer layer. 3 commercial and 4 experimental veneering ceramics ( n = 3 per group) were used to obtain different Δ α varying from −1.3 ppm/°C to +3.2 ppm/°C, which were determined by dilatometric analyses. Results Veneer fractures were observed in samples with Δ α ≥ +2.3 or ≤−0.3 ppm/°C. Residual stress profiles measured in other groups showed compressive stresses in the surface, these stresses decreasing with depth and then becoming more compressive again near the interface. Small Δ α variations were shown to induce significant changes in residual stress profiles. Compressive stress near the framework was found to decrease inversely to Δ α . Significance Veneer CTE close to Y-TZP (+0.2 ppm/°C Δ α ) gived the most favorable stress profile. Yet, near the framework, Δ α -induced residual stress varied inversely to predictions. This could be explained by the hypothesis of structural changes occurrence within the Y-TZP surface. Consequently, the optimum Δα value cannot be determined before understanding Y-TZP's particular behavior when veneered. [ABSTRACT FROM AUTHOR]

Introduction: This in-vitro study investigated the initial 24h bond strength between different composites and zirconia after application of four different adhesive systems. Methods: A total of 120 specimens of zirconia (InCoris, Sirona, Germany, Bernsheim) were ground with a 165 μm grit rotating diamond disc. Thirty specimens were each additionally treated with Cimara Zircon "CZ" (VOCO GmbH, Germany, Cuxhaven), Futurabond U "FBU" (VOCO GmbH), Futurabond M+ "FBM" (VOCO GmbH) or Futurabond M+ in combination with the DCA activator "FBMD" (VOCO GmbH). One of three different types of composites – BifixSE ("BS"), BifixQM ("BQ") or GrandioSO ("G") (VOCO GmbH) - was bonded to ten specimens each in every group. Shear bond strength (SBS) was determined in a universal testing machine. Statistical analysis was performed with ANOVA and the Tukey test. Results: FBM and FBMD gave higher SBS than CZ and FBU in combination with all tested composites. In comparison to FBU, FBM gave statistically significant increases in SBS with BifixSE (19.4±5.7 MPa) (P<0.013) and with GrandioSO (19.1±4.4 MPa) (P<0.021). None of the other comparisons was statistically significant. Conclusion: The new 10-MDP-containing adhesive systems FBM and FBMD increases initial SBS between composites and zirconia in comparison to CZ and FBU. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the wetting behaviour of a molten feldspathic glass-ceramic which is used as a veneering layer on dental Y-TZP cores. The grain size effect of the zirconia substrate on the wettability of the veneering material was also studied. It is suggested that the presence of a weak bond at the interface could be attributed to the poor wetting of ZrO2 surface by the molten veneer. Result of the sessile drop analysis showed high contact angles of more than 110˚ at the initial states of the test. The contact angles were affected by increasing the grain size. An about 6% increase in mean of the contact angles of micro Y-TZP was determined when compared to the nano-structured bodies. It is suggested that the fine microstructure which was observed in the nano Y-TZP body enhances the physical wetting behaviour due to a probable increase in surface energy which is considered as the driving force of wetting. The enhancement which was observed in wettability of the nano-sized Y-TZP at longer times may also be originated from a chemical wetting assisted by the diffusion of the atoms through the increased defects of surface such as grain boundaries and triple junctions. [ABSTRACT FROM AUTHOR]

Mechanical mastication is becoming a common fuel management treatment to reduce vertical fuel connectivity, as well as crown fire initiation and potential fire-line intensity, but the moisture dynamics of these novel fuel types have been largely unstudied. We recorded concurrent in situ meteorological observations with moisture and temperature profiles (at depths of 5 and 13 cm) for masticated fuel beds in three treatments in a lodgepole pine ( Pinus contorta Dougl. var. latifolia Engelm.) - black spruce ( Picea mariana (Mill.) B.S.P.) boreal stand located in the Upper Foothills of west-central Alberta. Mulch at the 5 cm depth remained at or near 100% moisture content for a majority of the observation period within the treatment that lacked any residual canopy cover. Only during a 10-day rain-free period was substantial drying observed at a depth of 5 cm. At the interface with the underlying duff layer, mulch remained at upwards of 150% moisture content. Drying was typically <10% of potential evaporation rates, except on days after rain, when drying equal to 25%-100% of potential evaporation was observed. Thermal properties of the mulch showed approximately five times the thermal diffusivity of soils, but less than a fuel crib, suggesting that masticated fuel beds have a thermal and moisture regime more similar to soils than fuel cribs, with a diffusion-dominated regime enhanced by minor advection. Low moisture movement observed from depth to the surface promoted highly variable surface moisture that created surface mulch with temperatures far in excess of air temperatures during periods of full sun. Such excess temperatures are shown to be an efficient indicator of surface dryness and high ignition probability. [ABSTRACT FROM AUTHOR]

Particles are frequently exposed to shear stresses during manufacturing, which leads to breakage. This is particularly relevant to weak active pharmaceutical ingredients and is prevalent in pharmaceutical and food industries. The attrition of paracetamol and aspirin caused by shear deformation at very low stresses is investigated here. The extent of breakage of these particles is related to the prevailing shear stresses and strains. In contrast to the expected trend, smaller particles exhibited increased breakage rates. At the onset of shearing at low stresses aspirin particles experienced slightly more breakage than the paracetamol, however prolonged shearing resulted in greater breakage of paracetamol. Breakage occurred initially through chipping with some fragmentation, particularly more noticeable for aspirin, with an increase in abrasion after extensive shear strain for paracetamol. Empirical breakage relationships are proposed and when combined with process stresses and strain analyses the extent of breakage occurring in process equipment can be estimated. [ABSTRACT FROM AUTHOR]

The performance of coppice harvesting machines is influenced by parameters such as field yield, the shape and size of the plantation and the space for turning at the headland. The quality of chips and the effect of the dendrometric characteristic of nine different species ( Fraxinus angustifolia, Robinia pseudoacacia, Salix alba, Eucalyptus occidentalis, Populus nigra L. and four genotypes of Populus x euroamericana (Grimminge, Hoogvorst, Muur, Vesten) grown in the same flat plot of about 4.5 ha on the performance rate and quality of the work, was evaluated. Field yields ranged from 33 t ha −1 to ∼95 t ha −1 , for the S. alba and E. occidentalis, respectively. The harvester worked with an average speed of 0.91 m s −1 (±0.22) and average productivities of 0.98 ha h −1 (±0.24) and 45.25 t h −1 (±5.56). There was a satisfactory linear correlation between the working speed of the machine and field yield. The quality of the chips showed some variability with values of moisture content ranging between 42.7% and 57.3% (for R . pseudoacacia and S. Alba respectively) and values of bulk density from 273 kg m −3 to 313 kg m −3 (for Populus euroamericana Vesten and E . occidentalis respectively). [ABSTRACT FROM AUTHOR]

Objectives: Thisprospectiveclinicalstudycomparedtheperformanceof implant-retained(study group) and tooth-retained (control) zirconia based fixed dental prostheses (FDPs) with at least 4 units. The null-hypothesis stated that complication rates in both groups are equally distributed. Methods: The study included patients in need of one 4- to 6-unit implant- or tooth-retained FDP each. All patients were examined 2 weeks after insertion (baseline) and then at 6 month intervals up to 3 years. At follow-up all restorations were examined for framework fracture, chipping, marginal integrity, surface roughness and biological complications. Kaplan-Meier estimation was used for data analysis. Results: 20 patients received tooth-retained and 7 patients implant-retained FDPs. The study was halted early when differences in chipping rates reached a statistically significant level. One FDP in the study group was lost due to implant abutment failure. FDP related chipping rates were 71% in the study group (mean observation time 32 months) and 15% in the control (mean observation time 34 months). Unit (abutment crown/pontic) related chipping rates were 32% in the study group and 6% in the control. Chipping rates differed statistically significant (log-rank test, p < .05). However, all ceramic defects could be corrected by grinding and polishing. No framework fracture was detected. Conclusions: Within the study limitations, survival rates seem satisfactorily in both implantand tooth retained long-span zirconia based FDPs. However, implant-supported FDPs seem more susceptible to veneering ceramic chippings. Clinical significance: The high chipping rates found in this study discourage the use of longspan implant-retained FDPs with zirconia frameworks. [ABSTRACT FROM AUTHOR]

Mechanical mastication is a fuel management technique that disrupts the vertical continuity of forest fuels by shredding of trees and understory vegetation into a highly compacted surface fuel bed. Despite the increasing application of mastication to manage wildfire risk, there is little information to date on fuel moisture in masticated fuels and optimal ignition patterns for prescribed burning. We investigated the applicability of the Fine Fuel Moisture Code (FFMC), a component of the Canadian Fire Weather Index (FWI) System, in tracking the diurnal and day-to-day changes in masticated surface fuel moisture, and developed a calibration of the standard conversion between moisture content and FFMC via regression modelling. We also proposed several modifications to the FFMC model (including a solar radiation driven fuel temperature) to better estimate the fuel-specific parameters of small diameter (< 1 cm) masticated surface fuels. Model validation was performed using destructive moisture content observations from a mastication treatment in west-central Alberta, Canada. A calibrated form of the moisture content to FFMC conversion produced mean error of -- 2.3% moisture content, and closely resembled previous FWI System calibrations for fast drying surface fuels. Our modified FFMC-based model fit well with field observations, and was capable of producing mean error of 1.0% moisture content. The fast drying that we observed highlights the need to better understand moisture dynamics of masticated fuel beds. [ABSTRACT FROM AUTHOR]

This investigation evaluated the impact of multiple firings during the veneering process of anterior all-ceramic restorations on the fracture load (FL) of zirconia crowns veneered with different ceramics (ZRT, ZRO, HFZ, STR). All-ceramic crowns with anatomically reduced zirconia frameworks were prepared using four different veneering ceramics (N = 192/n = 48 per veneering ceramic). The crowns were fired 2 and 10 times. Half of them were thermocycled (5000 cycles, 5 °C/55 °C, 20s). FL using Voss shear test was measured. Data was analyzed using ANOVA with partial eta squared and post-hoc Scheffé-test as well as t -test and Weibull analysis. Regarding FL, greatest differences were among the number of firings (p<0.001, η p 2 = 0.369). FL was not influenced by the interaction of both number of firings and aging level (p = 0.231) and the interaction of number of firings and veneering ceramic (p = 0.222). Differences were found comparing FL values of ZRT and STR (p<0.001) and of HFZ and STR (p<0.001). No differences occurred among the veneering ceramics after 2 (p = 0.430) and after 10 firings (p = 0.057) in respect to initial FL. For all initially tested veneering ceramics, FL showed higher values after 10 firings (p≤0.001–0.014). When aged, ZRO, HFZ, and STR also provided higher FL values after 10 firings (p≤0.001). For ZRT, FL values differed between initial and aged testing after 2 firings (p = 0.001) with aged specimens providing higher FL values. After 10 firings, none of the veneering ceramics showed differences regarding FL values between initial and aged testing. Weibull modulus was higher for ZRT specimens after 10 firings when tested initially (m = 10.1) and for aged ZRT specimens after 2 firings (m = 11.1). Failures occurred either with chipping of the veneer or total fracture. Veneered zirconia restorations tested presented higher FL after 10 firings compared to 2 firings. Aging via thermocycling showed a positive effect on the FL. [Display omitted] • Veneered zirconia restorations presented higher fracture load after 10 firings compared to 2 firings. • Aging via thermocycling often showed a positive effect on the fracture load. • The leucite-free veneering ceramic conducted the highest Weibull moduli after 10 firings for initial and aged testing. • Failures occurred either with chipping of the veneer or total fracture. [ABSTRACT FROM AUTHOR]

Objectives This in vitro study evaluated the impact of cements and implant analogs with different e-moduli on marginal adaptation, chipping, and the fracture resistance of zirconia crowns. Methods 80 crowns (Cercon, DeguDent) were manufactured for 40 polyoxymethylene (POM) and 40 titanium (Ti) one-piece implant analogs and divided into 10 groups: A, zinc oxide phosphate (Hoffmann׳s Cement, Richter&Hoffmann, Berlin, D); B, zinc oxide eugenol (Temp Bond, KerrHawe, Bioggio, CH); C, resin (Variolink II, Ivoclar-Vivadent, Schaan, FL); D, zinc oxide without eugenol (Temp Bond NE, KerrHawe, Bioggio, CH); E, glass ionomer (Ketac Cem, 3M ESPE, Seefeld, D). All samples were thermally mechanically loaded (1.2×10(6)×50 N; 3000×5 °C/55 °C). Marginal adaptation was semiquantitatively evaluated before and after ageing with a scanning electron microscope. After ageing, intact samples underwent a fracture resistance test. Results The best sealed margins before ageing were achieved with resin and zinc oxide cement and with resin after ageing. Zinc oxide samples showed the most discontinuously sealed margins after ageing and the difference between POM and Ti samples was significant only for zinc oxide. The numbers of samples failing during TCML were as follows: A(Ti − POM)=0−1; B(Ti − POM)=0−5; C(Ti − POM)=1/1; D(Ti − POM)=2−2; E (Ti − POM)=0−2. Fracture resistance test [N]: A(Ti − POM)=1181−801; B(Ti − POM)=1469−1517; C(Ti − POM)=1704−1408; D(Ti − POM)=1992−883; E (Ti − POM)=2750−1015. Conclusions TCML reduced the number of perfectly sealed samples and increased the number of chipped samples cemented onto POM implants with zinc oxide. This study could not show any significant impact on the fracture resistance of zirconia when different cements and implant analogs were used. [ABSTRACT FROM AUTHOR]

The developed technique for conducting a multilevel study of the operational characteristics, wear, thermal and stress state of ceramic tools has been described. A correlation between the cutting speed and operational characteristics, as well as the thermal state of the cutters with inserts from nitride ceramics, is revealed. Both peculiarities of the tool wear and the role of the thermal factor in the wear mechanism are determined. [ABSTRACT FROM AUTHOR]

Advanced high-strength steels are being used widely in automotive industry to achieve lightweight construction and fuel efficiency. During advanced high-strength steel blanking, the die components have to sustain higher pressure, and this may result in some problems such as chipping, cracking, galling and severe die wear, which has a great effect on the die life. This study aims to investigate the wear resistance performances of five die materials (carburized 4Cr13, conventional SKD11, Caldie, A2 and tungsten steel D60) using a featured blanking die setup combining five different die materials. The surface topography and microstructure of punching die materials are measured by optical profilometer and microscope. Based on the measured results, the specified wear rate and worn profiles of die inserts are obtained and compared. It is demonstrated that Caldie and A2 have higher wear resistance performance than SKD11 and 4Cr13. Moreover, the experimental results display that the most severe wear locations occur at the interfaces of straight lines and circular arcs. [ABSTRACT FROM PUBLISHER]

We examined two practical methods for reducing moisture content and/or ash content in biomass from southern pine harvests. Logging residues are a potential bioenergy feedstock, but contaminants can increase ash content during collection. We found that trommel screens can reduce ash levels in grindings from southern pine roundwood and clean chipped logging residues from 4.0 to 1.4 % and 11.9 to 6 %, respectively. Green whole-tree chips are a widely used form of forest biomass, but are 50 % moisture. Felling and transpirationally drying in-field before chipping reduced moisture from 53 to 43 % and 39 % in 4 and 8 weeks, respectively, without changing ash content (<0.7 %). Finally, we used data from the screening and drying studies in a simulation study to estimate delivered costs for whole-tree chipping and screened and unscreened grinders processing logging and clean chip residue. Whole-tree chipping provided the lowest cost option at ash content levels less than 1 %, and unscreened grinding of clean chip residue produced the least expensive option at 5 % ash. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the clinical performance of glass-ceramic/zirconia crowns fabricated using intraoral digital impressions - a retrospective study with a three-year follow-up. Methods: 70 consecutive patients with a total of 86 glass-ceramic/zirconia crowns were treated by a single clinician using standardized clinical and laboratory protocols. A complete digital workflow was adopted for the purpose except for the veneering procedure for the glass-ceramic crowns. Occlusal adjustments were made before the ceramic glazing procedure. Before cementation, all abutments where carefully cleaned with a 70% alcoholic solution and air dried. Cementation was performed using dual-curing, self-adhesive resin cement. Patients were re-examined after 12, 24 and 36 months, to assess crown chipping/ fractures. Results: After the three-year follow-up, none of the zirconia-based restoration was lost ("apparent" survival rate 100%) otherwise, the chipping rate of the veneering material increased from 9.3% after 12 months, to 14% after 24 months to 30.2% after 36 months. As a consequence, the " real " success rate after 3 years was 69.8%. Conclusions: After 3 years the success rate of zirconia-based crowns was 69.8%, while the incidence of the chipping was 30.2%. Assuming an exponential increase in chipping rate between 12 and 36 months it can be argued that, among others, the fatigue-mechanism could be advocated as the main factor for the failure of glass-ceramic veneered zirconia especially after 24 months. [ABSTRACT FROM AUTHOR]

Abstract: Nowadays wood chips produced from raw material of inferior quality are mainly used to feed domestic and industrial boilers. For this use, a good chip size distribution and low manufacturing energy consumption are required. Cutting forces are still inaccurately measured during the wood chipping process, which implies the use of oversized chippers' motors. A test bench for chipping wood under reasonably realistic conditions of industrial production is improved by adding an indirect force measurement system with high bandwidth of 3 KHz. The dynamic experimentations give the data needed to compute the curve presenting the vertical component of the cutting force, which is composed of three sections; the first one presents the values of the impact force; the second one is relatively straight and it refers to shear stress in wood; the third section corresponds to the period between two crosscuts. [Copyright &y& Elsevier]

Utilising logging residues (termed brash in the UK) for energy production has become a focus for energy providers since the development of specialist baling machinery to improve the logistical and financial potential of this material. To explore a farm-scale operations scenario, brash from a mixed conifer, temperate zone forest was baled and chipped with commercial machinery to produce fuel-grade woodchip. Clear-fell logging procedures presented a range of brash configurations to facilitate baling machinery to produce compacted, tied, regular sized bales. Average hourly bale production and fresh weight tonnage output was 28 ± 2 bales/h and 12.4 t/h respectively. Extraction of bales and stacking along access road verges achieved an average 24 ± 2 bales/h. Woodchipping output averaged 11.8, 13.7 and 13.0 green t/h respectively for whole bale, log only and bale-log composite woodchip. Chipping production efficiency was affected by bale condition, handling and machinery performance but chiefly by site transport accessibility and logistical planning. The average total cost of in-farm delivered fuel quality woodchip product from brash bales was £25.22 (€29.67) per green tonne. Brash bale chips contained more than double the percentage of fines <6.3 mm compared to round log woodchips and also had significantly higher gross energy and nutrients content. Brash bale moisture content was observed to fluctuate widely and nutrients and energy content reduced during the 3-yr monitoring period. In conclusion, the combination of equipment and the confined production scenario was a viable process that provided fuel-grade woodchip at relatively low cost. [ABSTRACT FROM AUTHOR]

We conducted a comparative study of chipping logging residues at the roadside landing or at the yarder pad, the latter inaccessible to heavy road vehicles. Field data was collected from real operations in the Italian mountain, and it was used for building a simulation model that could generalize the results of the study. The model was built with Arena 14 and carefully reflected interaction delays between individual units along the chain. Chipping at the pad with a chipper and two shuttles was the best compromise solution of low supply cost and fuel consumption. At a mean cost of €22.7 per fresh tonne, this solution was 10% cheaper than chipping at the landing. Using three chip shuttles did not allow a meaningful reduction of supply cost over a two-shuttle chain, but resulted in a 7% increase of fuel consumption. The distance between the pad and the roadside landing was by far the most important factor in determining supply cost, and accounted for 80% of the variability in the data, for both systems. Under these circumstances, the higher speed and payload of the chip shuttles made it preferable to chip at the pad, provided enough shuttles are available. [ABSTRACT FROM PUBLISHER]

Objectives: The aim was to investigate the influence of cusp inclinations and curvatures on the failure behaviour and fracture resistance of veneered zirconia crowns. Materials and methods: Five groups ( n = 8/group) of zirconia-based molar crowns were fabricated by modifying cusp inclination (S, steep = 45°; M, medium = 30°; F, flat = 10°) and curvature (P, pointed; R, round; O, round-oblate). Combinations MP, MR, SP, SR and FO were investigated. All crowns were fixed on polymethylmethacrylate teeth, thermally cycled and mechanically loaded. Failures were monitored and fracture resistance was determined after ageing. Crowns were fractographically analysed with scanning electron microscopy. Results: Chipping during thermal cycling and mechanical loading (TCML) was observed in groups MR (1×), SP (6×) and SR (3×). Defect sizes varied between 0.12 mm (MR) and 17.28 mm (SP). Failures started from occlusal contacts. Mean fracture varied significantly between 1,354.2 ± 360.0 N (SR) and 3,155.8 ± 444.4 N (FO). Conclusions: Cusp inclination and curvature influenced failures during TCML and fracture loads. Crowns with medium cusp inclination and pointed or round curvature are recommended for clinical application as they revealed high resistance to chipping. Steep inclination, especially in combination with pointed curvature, was shown to increase chipping rates and areas and to decrease fracture force. Clinical relevance: The results show the necessity of considering design parameters of the veneer in order to reduce failures of zirconia-based crowns. [ABSTRACT FROM AUTHOR]

Abstract: Evaluation of the cutting tool is an important aspect when a machining process is monitored. At this time, microgeometry of the cutting edge is very frequently used term. It has a great influence on the cutting process and it is necessary to know how correctly to measure parameters of the cutting edge to ensure reliability and repeatability. Nowadays, many devices exist on the market which can be used for measuring the cutting edge. They are based on tactile or optical principles. Parameters of the cutting edge have a great influence on tool life and therefore it is important to measure them correctly. Primarily the radius of the cutting edge and the K factor is usually monitored. This paper deals with measuring parameters on the cutting edge such as radius of the cutting edge, K factor and roughness of the surface, chipping, and their evaluation when machining special alloy Inconel 718 which is used mainly in the aerospace industry. Other measuring methods for tool life will be presented. [Copyright &y& Elsevier]

Nowadays, dental zirconia is widely used as a framework material for a fixed dental prosthesis as well as a single restoration. However, clinical studies have reported high incidence of veneer chipping of zirconia-ceramic restorations compared to that of metal-ceramics. Several factors were raised as the possible causes of veneer ceramic chipping, however, it is still in debate. Recently, residual stresses in the veneer ceramics after cooling process gathers attention as one possible cause of chipping and many studies reported that the rate of cooling significantly influenced the types and the amount of residual stress. The purpose of current review was to briefly describe the effect of cooling rate on the residual stress in zirconia-ceramics. It was also described that the different behavior of residual stress between zirconia-ceramics and metal-ceramics following different cooling rate. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: Veneered zirconia restorations predominately fail due to veneering fractures. It is hypothesized that a cusp-supporting framework design can prevent these catastrophic failures in all-ceramic restorations. Therefore, we investigated the influence of framework design and framework material on the stress distribution in a single tooth restoration using the numerical finite element method. Methods: A three-dimensional model of a veneered lower molar (36) crown with constant outer shape was used. The framework design was either cusp supporting or with a constant framework thickness. Zirconia, alumina, and a gold alloy were used as framework material. A glass ceramic material was used as veneering material for both cases. Two different load cases were simulated: terminal occlusion with load distributed over the occlusal surface of the tooth and a fairly extreme load case with all force concentrated on one cusp. Results: Maximum tensile stresses in the glass ceramic veneering material concentrated in the fissure region for all models. A cusp supporting framework design decreased the maximum tensile stresses significantly up to 30.5%. The distolingual load case resulted in an approximately fourfold higher stress level compared to the terminal occlusion load case. Significance: A cusp supporting framework design can significantly decrease the maximum tensile stresses in the veneering material of single crowns. Based on the numerical results of this study it can be expected that such a design could decrease the risk of veneering failure in vivo. [Copyright &y& Elsevier]

Abstract: Objective: The aim of this study was to investigate the influence of increasing veneering porcelain thickness in clinically representative zirconia molar crowns on the residual stresses under fast and slow cooling protocols. Methods: Six veneered zirconia copings (Procera, Nobel Biocare AB, Gothenburg, Sweden) based on a mandibular molar form, were divided into 3 groups with flattened cusp heights that were 1mm, 2mm, or 3mm. Half the samples were fast cooled during final glazing; the other half were slow cooled. Vickers indentation technique was used to determine surface residual stresses. Normality distribution within each sample was done using Kolmogorov–Smirnov & Shapiro–Wilk tests, and one-way ANOVA tests used to test for significance between various cusp heights within each group. Independent t-tests used to evaluate significance between each cusp height group with regards to cooling. Results: Compressive stresses were recorded with fast cooling, while tensile stresses with slow cooling. The highest residual compressive stresses were recorded on the fast cooled 1mm cusps which was significantly higher than the 2 and 3mm fast cooled crowns (P <0.05). There was a significant linear trend for residual stress to decrease as veneering porcelain thickness increased in the fast cooled group (P <0.05). No significant differences were found between the various cusp heights during slow cooling (P ≥0.05). Significance: Cooling rate and geometric influences in a crown anatomy have substantially different effects on residual stress profiles with increasing veneering porcelain thickness compared to the basic flat plate model. [Copyright &y& Elsevier]

Abstract: Objectives: The residual stress profile developed within the veneering ceramic during the manufacturing process is an important predicting factor in chipping failures, which constitute a well-known problem with yttria-tetragonal-zirconia polycrystal (Y-TZP) based restorations. The objectives of this study are to measure and to compare the residual stress profile in the veneering ceramic layered on three different polycrystalline ceramic framework materials: Y-TZP, alumina polycrystal (AL) and zirconia toughened alumina (ZTA). Methods: The stress profile was measured with the hole-drilling method in bilayered disk samples of 19mm diameter with a 0.7mm thick Y-TZP, AL or ZTA framework and a 1.5mm thick layer of the corresponding veneering ceramic. Results: The AL samples exhibited increasing compressive stresses with depth, while compressive stresses switching into interior tensile stresses were measured in Y-TZP samples. ZTA samples exhibited compressive stress at the ceramic surface, decreasing with depth up to 0.6mm from the surface, and then becoming compressive again near the framework. Significance: Y-TZP samples exhibited a less favorable stress profile than those of AL and ZTA samples. Results support the hypothesis of the occurrence of structural changes within the Y-TZP surface in contact with the veneering ceramic to explain the presence of tensile stresses. Even if the presence of Y-TZP in the alumina matrix seems to negatively affect the residual stress profiles in ZTA samples in comparison with AL samples, the registered profiles remain positive in terms of veneer fracture resistance. [Copyright &y& Elsevier]

Abstract: The demand for the use of nickel-based superalloy such as Inconel 718 is increasing in aerospace industry as it is efficient for energy and has excellent properties. In this paper, the experimental studies of tool wear mechanism and tool life in ball nose end milling of Inconel 718 is presented under minimum quantity lubricant (MQL) condition. The evaluations of the results are focusing on the comparison of up-milling and down-milling operations using physical vapor deposition (PVD) - coated carbide inserts. Machining parameters; depth of cut, feed rate and cutting speed are considered during the evaluation. The experimental results showed that down-milling operation has better results in terms of tool wear than up-milling operation. Chipping on cutting tool edge was the primary reason that responsible to notch wear with prolong machining. [Copyright &y& Elsevier]

Objectives: The first objective of this study was to retrospectively evaluate zirconia-based restorations (ZBR). The second was to correlate failures with clinical parameters and to identify and to analyse chipping failures using fractographic analysis. Methods: 147 ZBR (tooth- and implant-supported crowns and fixed partial dentures (FPDs)) were evaluated after a mean observation period of 41.5 ±31.8 months. Accessorily, zirconia implant abutments (n = 46) were also observed. The technical (USPHS criteria) and the biological outcomes of the ZBR were evaluated. Occlusal risk factors were examined: occlusal relationships, parafunctional habits, and the presence of occlusal nightguard. SEM fractographic analysis was performed using the intra-oral replica technique. Results: The survival rate of crowns and FPDs was 93.2%, the success rate was 81.63% and the 9-year Kaplan-Meier estimated success rate was 52.66%. The chipping rate was 15% and the framework fracture rate was 2.7%. Most fractographic analyses revealed that veneer fractures originated from occlusal surface roughness. Several parameters were shown to significantly influence veneer fracture: the absence of occlusal nightguard ( p = 0.0048), the presence of a ceramic restoration as an antagonist ( p = 0.013), the presence of parafunctional activity ( p = 0.018), and the presence of implants as support ( p = 0.026). The implant abutments success rate was 100%. Conclusions: The results of the present study confirm that chipping is the first cause of ZBR failure. They also underline the importance of clinical parameters in regards to the explanation of this complex problem. This issue should be considered in future prospective clinical studies. Clinical significance: Practitioners can reduce chipping failures by taking into account several risk parameters, such as the presence of a ceramic restoration as an antagonist, the presence of parafunctional activity and the presence of implants as support. The use of an occlusal nightguard can also decrease failure rate. [ABSTRACT FROM AUTHOR]

PURPOSE. To evaluate the effects of surface treatments on shear bond strength (SBS) between microwave and conventionally sintered zirconia core/veneers. MATERIALS AND METHODS. 96 disc shaped Noritake Alliance zirconia specimens were fabricated using YenaDent CAM unit and were divided in 2 groups with respect to microwave or conventional methods (n=48/group). Surface roughness (Ra) evaluation was made with a profilometer on randomly selected microwave (n=10) and conventionally sintered (n=10) cores. Specimens were then assessed into 4 subgroups according to surface treatments applied (n=12/group). Groups for microwave (M) and conventionally (C) sintered core specimens were as follows; MC,CC: untreated (control group), M1,C1:Al2O3 sandblasting, M2,C2:liner, M3,C3:Al2O3 sandblasting followed by liner. Veneer ceramic was fired on zirconia cores and specimens were thermocycled (6000 cycles between 5°-55°C). All specimens were subjected to SBS test using a universal testing machine at 0.5 mm/min, failure were evaluated under an optical microscope. Data were statistically analyzed using Shapiro Wilk, Levene, Post-hoc Tukey HSD and Student's t tests, Two-Way-Variance- Analysis and One-Way-Variance-Analysis (α=.05). RESULTS. Conventionally sintered specimens (1.06 ± 0.32 μm) showed rougher surfaces compared to microwave sintered ones (0.76 ± 0.32 μm)(P=.046), however, no correlation was found between SBS and surface roughness (r=-0.109, P=.658). The statistical comparison of the shear bond strengths of C3 and C1 group (P=.015); CC and MC group (P=.004) and C3 and M3 group presented statistically higher (P=.005) values. While adhesive failure was not seen in any of the groups, cohesive and combined patterns were seen in all groups. CONCLUSION. Based on the results of this in-vitro study, Al2O3- sandblasting followed by liner application on conventionally sintered zirconia cores may be preferred to enhance bond strength. [ABSTRACT FROM AUTHOR]

Sentinel (FV8957-10) is a new yellow-fleshed potato cultivar that produces a high yield of attractive round to oval tubers at early harvest. Sentinel is suitable for fresh market use and chip processing. It was selected at the Lethbridge Research Centre of Agriculture and Agri-Food Canada, AB from a cross made at the Potato Research Centre of Agriculture and Agri-Food Canada, NB between breeding clones F72218 and F47024. Sentinel has erect medium-height vines and produces uniform tubers of medium-size with a light buff skin, light yellow flesh and shallow eyes. In multi-date-harvest trials, Sentinel produced similar or higher marketable yield compared to Atlantic and NorValley in southern Alberta. When harvested at 80 days after planting, Sentinel produced similar or greater yield than Superior and Conestoga at test sites across western Canada. Specific gravity of Sentinel was less than Atlantic and Conestoga but higher than NorValley and Superior, whereas chip colour was similar to Atlantic and lighter than NorValley or Superior. Sentinel showed little tendency to slough or to darken after cooking. It showed clear foliar and tuber symptoms when infected with bacterial ring rot. Sentinel is moderately susceptible to verticillium wilt, early blight, fusarium wilt and common scab and susceptible to late blight. [ABSTRACT FROM AUTHOR]

Objective. Over the last several years, the Finite Element Analysis (FEM) has been widely recognized as a reference method in different fields of study, to simulate the distribution of mechanical stress, in order to evaluate the relative distribution of loads of different nature. The aim of this study is to investigate through the FEM analysis the stress distribution in fixed prostheses that have a core in Zirconia and a ceramic veneer supported by implants. Materials and methods. In this work we investigated the mechanical flexural strength of a ceramic material (Noritake®) and a of zirconium framework (Zircodent®) and the effects of the manufacturing processes of the material commonly performed during the production of fixed prostheses with CAD/CAM technology. Specifically three point bending mechanical tests were performed (three-point-bending) (1-3), using a machine from Test Equipment Instron 5566®, on two structures in zirconium framework-ceramic (structures supported by two implant abutments with pontic elements 1 and 2). A further in-depth analysis on the mechanical behavior in flexure of the specimens was conducted carrying out FEM studies in order to compare analog and digital data. Results. The analysis of the data obtained showed that the stresses are distributed in a different way according to the intrinsic elasticity of the structure. The analysis of FPD with four elements, the stresses are mainly concentrated on the surface of the load, while, in the FPD of three elements, much more rigid, the stresses are concentrated near the inner margins of the abutments. The concentration of many stresses in this point could be correlated to chipping (4) that is found in the outer edges of the structure, as a direct result of the ceramic brittleness which opposes the resilience of the structure subjected to bending. Conclusions. The analysis of the UY linear displacement confirms previous data, showing, in a numerical way, that the presence of the ceramic is related to the lowering of the structure. So, the reference values are those of the linear lowering obtained in the Mechanical Test and in our FEM analysis. . zirconium framework with four elements 4,227 10-2mm. . zirconium framework with ceramic structure with four elements 2,266 10-2 mm. That suggests that the presence of ceramics halves the flexion capabilities of the prosthetic materials. [ABSTRACT FROM AUTHOR]