Application of a bionic ring structure on drill pipe surfaces to improve the performance of anti-corrosion coatings

2016 ◽  
Vol 63 (3) ◽  
pp. 177-183 ◽  
Author(s):  
Yunhai Ma ◽  
Hubiao Wang ◽  
Xin Zhang ◽  
Wenbo Shang ◽  
Jin Tong ◽  
...  
Keyword(s):  
Bond Strength ◽  
Drill Pipe ◽  
Ring Structure ◽  
Ring Groove ◽  
Content Type ◽  
Mechanical Adhesion ◽  
Wide Range ◽  
Bionic Structure ◽  
Bond Strengths ◽  
The Difference

Purpose Nature provides a wide range of structures with different functions, which can serve as a source of research concepts. Based on the bionics principle, a bionic structure was applied to drill pipe specimens to compare the bond strength of paint coatings with and without a bionic ring groove pattern machined on the substrate. Design/methodology/approach Using the Revetest Xpress Plus scratch tester, the bond strengths of the coatings on the drill pipe with and without the bionic structure were measured and the difference in bond strength was observed. Findings The critical scratch loads of the surface coatings were 12.77 and 5.4 N. Furthermore, the scratch curve from the plain sample had a larger fluctuation compared to the curve of the samples with bionic ring grooves. Originality/value This indicated that the application of a bionic pattern to the surface of the substrate could enhance the bond strength and the degree of mechanical adhesion between the coating and the surface of the drill pipe, which is beneficial for the anti-corrosion performance of the drill pipe.

scholarly journals Micro-push-out bond strength of Mineral—based root canal sealer in canals with different tapers.

2021 ◽  
Vol 10 (1) ◽  
pp. 1-7
Author(s):  
Nunna Vasavi ◽  
◽  
Kantheti Sirisha ◽  
Keyword(s):  
Bond Strength ◽  
Root Canal ◽  
Testing Machine ◽  
Root Canal Sealer ◽  
Rotary Instruments ◽  
Significant Difference ◽  
Ah Plus ◽  
Bond Strengths ◽  
The Difference ◽  
Push Out

Objective: The aim of this study was to assess the micro-push-out bond strength of a mineral-based root canal sealer, BioRoot RCS in canals prepared by K3XF rotary systems of two different tapers. Material and Methods: Eighty caries free maxillary central incisors were used in this study. The samples were allocated into 4 groups (n=20) according to the root canal sealer and taper of the rotary instruments. The samples were obturated using single cone obturation technique. From each root 1mm thick slices at coronal, middle and apical thirds were collected using hard tissue microtome under continuous water coolant. Push-out tests were done for these sections using a Universal testing machine (INSTRON 8801) at a crosshead speed of 1mm/min. One-way analysis of variance (ANOVA) was used to compare the bond strengths within groups and Tukey’s multiple post hoc analysis was used for pair-wise comparison of bond strengths. Results: AH Plus exhibited higher micro-push-out bond strength than BioRootRCS though they did not differ significantly (p>0.05). Preparation of root canals with 6% taper rotary instruments showed higher bond strength than 4% though they did not differ significantly (p>0.05). Conclusion: There was no significant difference between micro-push-out bond strength values of BioRoot RCS and AH Plus. The bond strength values were high in 6% taper canals than 4% canals though the difference was not significant statistically.

Design guidelines to mitigate distortion in material jetting specimens

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kamran Kardel ◽  
Ali Khoshkhoo ◽  
Andres L. Carrano
Keyword(s):  
Aspect Ratio ◽  
Layer Thickness ◽  
Design Guidelines ◽  
Geometrical Parameters ◽  
Content Type ◽  
Build Orientation ◽  
Aspect Ratios ◽  
Wide Range ◽  
The Difference ◽  
Part Thickness

Purpose The purpose of this paper is to investigate the effects of layer thickness, aspect ratio, part thickness and build orientation on distortion to have a better understanding of its behavior in material jetting technology. Design/methodology/approach Specimens with two layer thicknesses (14 and 28 µm) were printed in two aspect ratios (2:1) and (10:1), four thickness values (1, 2, 3 and 4 mm) and three build orientations (45d, XY and YX) and scanned with a wide-area 3D surface scanner to quantify distortion. The material used to build the test specimens was a commercially available resin, VeroWhitePlus RGD835. Findings The results of this study showed that all printed specimens by material jetting 3D printers had some level of distortion. The 1-mm thickness specimens, for both layer thicknesses of 14 µm and 28 µm, showed a wide range of anomalies including reverse coil set (RCS), reverse cross bow (RCB), cross bow (CB), wavy edge (WE) and some moderate twisting (T). Similar occurrences were observed for the 2-mm thickness specimens as there were RCS, WE, RCB and T anomalies that show the difference between the thinner specimens (1- and 2-mm) with the thicker ones (3- and 4-mm). In both 3- and 4-mm thickness specimens, there was more consistency in terms of distortion with mainly RCS and RCB anomalies. In total, six different types of flatness anomalies were found to occur with the following incidences: reverse coil set (91 specimens, 63.19%), reverse cross bow (50 specimens, 34.72%), wavy edge (23 specimens, 15.97%), twist (19 specimens, 12.50%), coil set (11 specimens, 7.64%) and cross bow (7 specimens, 4.86%). Originality/value This study expands the research on how the preprocess parameters such as layer thickness and build orientation and the geometrical parameters such as part thickness and aspect ratio cause dimensional distortion. Distortion is a pervasive consequence of the curing process in photopolymerization and explores one of the most common defects that come across in polymeric-based additive manufacturing. In addition to the characterization of the type and magnitude of distortion, the contributions of this work also include establishing the foundation for design guidelines aiming at minimizing distortion in material jetting.

Assessment of mechanical strength of nano silica concrete (NSC) subjected to elevated temperatures

2019 ◽  
Vol 10 (1) ◽  
pp. 90-109 ◽  
Author(s):  
Hala Mohamed Elkady ◽  
Ahmed M. Yasien ◽  
Mohamed S. Elfeky ◽  
Mohamed E. Serag
Keyword(s):  
Elevated Temperature ◽  
Bond Strength ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Nano Silica ◽  
Content Type ◽  
Post Exposure ◽  
Concrete Mix ◽  
Bond Strengths

Purpose This paper aims to inspect the effect of indirect elevated temperature on the mechanical performance of nano silica concrete (NSC). The effect on both compressive and bond strengths is studied. Pre- and post-exposure to elevated temperature ranges of 200 to 600°C is examined. A range covered by three percentages of 1.5, 3 and 4.5 per cent nano silica (NS) in concrete mixes is tested. Design/methodology/approach Pre-exposure mechanical tests (normal conditions – room temperature), using 3 per cent NS in the concrete mix, led to the highest increase in both compressive and bond strengths (43 per cent and 38.5 per cent, respectively), compared to the control mix without NS (based on 28-day results). It is worth noticing that adding NS to the concrete mixes does not have a significant effect on improving early-age strength. Besides, permeability tests are performed on NSC with different NS ratios. NS improved the concrete permeability for all tested percentages of NS. The maximum reduction is accompanied by the maximum percentage used (4.5 per cent NS in the NSC mix), reducing permeability to half the value of the concrete mix without NS. As for post-exposure to elevated-temperature mechanical tests, NSC with 1.5 per cent NS exhibited the lowest loss in strength owing to indirect heat exposure of 600°C; the residual compressive and bond strengths are 73 per cent and 35 per cent, respectively. Findings The dispersion technique of NS has a key role in NSC-distinguished mechanical performance with NSC having lower NS percentages. NS significantly improved bond strength. NS has a remarkable effect on elevated temperature endurance. The bond strength of NSC exposed to elevated temperatures suffered faster deterioration than compressive strength of the exposed NSC. Research limitations/implications A special scale factor needs to be investigated for the NSC. Originality/value Although a lot of effort is placed in evaluating the benefits of using nano materials in structural concrete, this paper presents one of the first outcomes of the thermal effects on concrete mixes with NS as a partial cement replacement.

Pharmacological comparison of endothelium-dependent relaxation in isolated cerebral and extracerebral arteries

1988 ◽  
Vol 69 (4) ◽  
pp. 580-587 ◽  
Author(s):  
Tadayoshi Nakagomi ◽  
Kazuhiro Hongo ◽  
Neal F. Kassell ◽  
Tomio Sasaki ◽  
R. Michael Lehman ◽  
...  
Keyword(s):  
Basilar Artery ◽  
Cerebral Arteries ◽  
Isometric Tension ◽  
Content Type ◽  
Wide Range ◽  
Basilar Arteries ◽  
The Common ◽  
The Difference ◽  
Endothelium Dependent Relaxation ◽  
Fine Print

✓ Endothelium-dependent relaxation was induced by acetylcholine (ACh), adenosine triphosphate (ATP), and thrombin in isolated cerebral and extracerebral arteries obtained from rabbits and dogs. Using an isometric tension-recording method, the authors then examined the difference in the extent of relaxation between the cerebral and extracerebral arteries. In rabbits, the dose-response curve of the basilar artery for ACh was significantly different (p < 0.05) from curves of the femoral and common carotid arteries. The IC50 value (the concentration inducing a one-half inhibition of the initial contractile tone) for the basilar artery in ACh-induced relaxation was significantly higher (p < 0.05) than for the common carotid artery, although the mean maximum relaxation of the basilar artery to ACh was not significantly different from that seen in extracerebral arteries. The relaxing effect of ACh in dogs was much less in the middle cerebral and basilar arteries than in the common carotid, vertebral, and femoral arteries. On the other hand, both ATP (in rabbits and dogs) and thrombin (in dogs) induced significantly more (p < 0.05) relaxation in the cerebral arteries than in the extracerebral arteries. Endothelium-dependent relaxation induced by ACh or ATP has been demonstrated in a wide range of arteries from a variety of animals. The present results suggest that ATP has a more important role than ACh in the regulation of the vascular tone of the major cerebral arteries in these two species.

Healing simulation for bond strength prediction of FDM

2017 ◽  
Vol 23 (3) ◽  
pp. 551-561 ◽  
Author(s):  
Timothy J. Coogan ◽  
David O. Kazmer
Keyword(s):  
Bond Strength ◽  
Fused Deposition Modeling ◽  
Processing Parameters ◽  
Temperature History ◽  
Coefficient Of Determination ◽  
Content Type ◽  
Fused Deposition ◽  
Diffusion Controlled ◽  
Deposition Modeling ◽  
Bond Strengths

Purpose The purpose of this paper is to present a diffusion-controlled healing model for predicting fused deposition modeling (FDM) bond strength between layers (z-axis strength). Design/methodology/approach Diffusion across layers of an FDM part was predicted based on a one-dimensional transient heat analysis of the interlayer interface using a temperature-dependent diffusion model determined from rheological data. Integrating the diffusion coefficient across the temperature history with respect to time provided the total diffusion used to predict the bond strength, which was compared to the measured bond strength of hollow acrylonitrile butadiene styr (ABS) boxes printed at various processing conditions. Findings The simulated bond strengths predicted the measured bond strengths with a coefficient of determination of 0.795. The total diffusion between FDM layers was shown to be a strong determinant of bond strength and can be similarly applied for other materials. Research limitations/implications Results and analysis from this paper should be used to accurately model and predict bond strength. Such models are useful for FDM part design and process control. Originality/value This paper is the first work that has predicted the amount of polymer diffusion that occurs across FDM layers during the printing process, using only rheological material properties and processing parameters.

Hybrid concretes: solutions for better bond and splitting tensile strength under elevated heat exposure

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hala Mohamed Elkady ◽  
Ola M. Bakr ◽  
Mohamed Kohail ◽  
Elsayed Abdel Raouf Nasr
Keyword(s):  
Compressive Strength ◽  
Elevated Temperatures ◽  
Heat Exposure ◽  
Content Type ◽  
Wide Range ◽  
Fire Endurance ◽  
Concrete Mechanical Properties ◽  
Bond Strengths ◽  
Modified Formula ◽  
Concrete Control

PurposeThis paper presents the second part of the investigation on resistance to elevated temperatures of a proposed hybrid composite concrete (NCSF-Crete) mix. The composite including nano metakaolin (NC) and steel fibers (SF) in addition to regular concrete components has proven -in the first published part-earlier promoted fresh concrete behavior, and to have reduced loss in compressive strength after exposure to a wide range of elevated temperatures. This presented work evaluates another two critical mechanical characteristics for the proposed composite -namely- splitting and bond strengths.Design/methodology/approachA modified formula correlating splitting and compressive strength (28 days) based on experiments results for NCSF is proposed and compared to formulas derived for regular concrete in different design codes. Finally, both spitting and bond strengths are evaluated pre- and post-exposure to elevated temperatures reaching 600 °C for two hours.FindingsThe proposed NCSF-Crete shows remarkable fire endurance, especially in promoting bond strength as after 600 °C heat exposure tests, it maintained strength equivalent to 70% of a regular concrete control mix at room temperature. Improving residual splitting strength was very significant up to 450 °C exposure.Research limitations/implicationsObvious deterioration is monitored in splitting resistance for all concretes at 600 °C.Practical implicationsThis proposed composite improved elevated heats resistance of the most significant concrete mechanical properties.Social implicationsUsing a more green and sustainable constituents in the composite.Originality/valueThe proposed composite gathers the merits of using NC and SF, each has been investigated separately as an addition to concrete mixes.

Malaysia property sector

2016 ◽  
Vol 9 (4) ◽  
pp. 468-482 ◽  
Author(s):  
Ema Izati Zull Kepili ◽  
Tajul Ariffin Masron
Keyword(s):  
Real Estate ◽  
Portfolio Diversification ◽  
Tax Rates ◽  
Property Market ◽  
Content Type ◽  
Average Return ◽  
Wide Range ◽  
The Difference ◽  
Liberalization Policy ◽  
Ranking Position

Purpose Because Malaysia decided to liberalize its property sector, investors have shown a considerable interest in the country’s property investment. Divided into five sub-sectors, Malaysia’s real estate is sought actively by foreign investors. However, to date, the sub-sectors performance analysis has never been researched for the purpose of investment diversification within the property sector. This paper aims to examine the performance of sub-sectors in the property market, namely, residential, commercial, industrial, agricultural and development land. This paper also assesses the portfolio diversification benefits within the sectors. Design/methodology/approach Quarterly data from 2002 or 2014 are used to analyze the performance of the Malaysia property market. The analysis is conducted in three phases, pre-liberalization, post-liberalization and overall period, because it considers the liberalization policy introduced in 2009. Statistically, the risk-adjusted return featuring Sharpe’s index is used to observe how these sub-sectors perform relative to each other. Correlation analysis is used to observe the existence of diversification benefits in terms of a Malaysia property context. Findings It is found that Malaysia’s real estate sub-sectors have different rankings during the pre- and post-liberalization periods. The difference is due to changes in their average return and the risk. During the post-liberalization period, risk for all sub-sectors has increased but has been well compensated by the return. The residential property sector maintains its ranking position as the best sub-sector for every risk investor’s encounter. Research limitations/implications Due to wide range of differences and non-uniformity of costs associated with housings, for example tax rates, rental stream, LTV and others, this research focuses on values and data supplied by NAPIC only. Originality/value Although performance and portfolio diversification benefits have been tested in many Asian countries, none has tried to assess the Malaysia property. This research enables the policy maker to be informed on whether the sub-sectors are performing in accordance to country’s requirement and which sub-sectors need to be improved further.

Exploring agency, knowledge and power in an Australian bulk cereal supply chain

2014 ◽  
Vol 19 (4) ◽  
pp. 431-444 ◽  
Author(s):  
Romona Byrne ◽  
Damien Power
Keyword(s):  
Supply Chain ◽  
Food Distribution ◽  
Supplier Relationships ◽  
Content Type ◽  
Referent Power ◽  
Wide Range ◽  
Institutional Differences ◽  
Management Roles ◽  
The Difference ◽  
Definition Of

Purpose – The purpose of this paper is to explore how information sharing practices influenced inter-firm relationships. This was done specifically in relation to bulk commodity supply chains, due to the pre-existing power asymmetries in the system. Design/methodology/approach – This research was conducted using an interpretivist, inductive approach. The intention was to gather a wide range of data and then explore the data to see which themes emerged, rather than focusing on collecting data relevant only to specific themes. Findings – The key findings of this research focused around the difference between creating situations of compliance or collaboration in a supply chain context. This suggests that by understanding the relationships that exist between organisations, those in procurement and supply chain management roles will be able to better understand and manage the nuances of their supplier relationships. Research limitations/implications – The study is focused on a supply network specifically configured to facilitate sourcing and distribution of bulk grain. As such the findings need to be understood within the constraints of this context. Practical implications – Reliance on coercive power in an institutional change process is shown in our study to create a situation of compliance rather than of collaboration. Reliance on a different type of power, such as referent power, would be more successful in creating a situation of collaboration. Social implications – The sourcing and distribution of bulk grain is fundamental to food distribution in a developed economy. Our study provides a set of propositions indicating where managers can focus to more effectively manage these flows. Originality/value – The definition of the “agent” also provided an interesting point of comparison. This research found that the ultimate definition of the “agent” changes and can be linked to the institutional differences in ownership within a supply chain. This suggests the potential to redefine the way that Agency theory is discussed. The notion that the “agent” is dynamic and is likely to be the “agent”, “caretaker” and more at the same time suggests the potential for the traditional definition of the agent to be challenged.

Comparative Effects of High-Tech Visual Scene Displays and Low-Tech Isolated Picture Symbols on Engagement From Students With Multiple Disabilities

2019 ◽  
Vol 50 (4) ◽  
pp. 693-702 ◽  
Author(s):  
Christine Holyfield ◽  
Sydney Brooks ◽  
Allison Schluterman
Keyword(s):  
Language Learning ◽  
Augmentative And Alternative Communication ◽  
Visual Analysis ◽  
Multiple Disabilities ◽  
Visual Scene ◽  
Future Research ◽  
High Tech ◽  
Single Subject ◽  
Wide Range ◽  
The Difference

Purpose Augmentative and alternative communication (AAC) is an intervention approach that can promote communication and language in children with multiple disabilities who are beginning communicators. While a wide range of AAC technologies are available, little is known about the comparative effects of specific technology options. Given that engagement can be low for beginning communicators with multiple disabilities, the current study provides initial information about the comparative effects of 2 AAC technology options—high-tech visual scene displays (VSDs) and low-tech isolated picture symbols—on engagement. Method Three elementary-age beginning communicators with multiple disabilities participated. The study used a single-subject, alternating treatment design with each technology serving as a condition. Participants interacted with their school speech-language pathologists using each of the 2 technologies across 5 sessions in a block randomized order. Results According to visual analysis and nonoverlap of all pairs calculations, all 3 participants demonstrated more engagement with the high-tech VSDs than the low-tech isolated picture symbols as measured by their seconds of gaze toward each technology option. Despite the difference in engagement observed, there was no clear difference across the 2 conditions in engagement toward the communication partner or use of the AAC. Conclusions Clinicians can consider measuring engagement when evaluating AAC technology options for children with multiple disabilities and should consider evaluating high-tech VSDs as 1 technology option for them. Future research must explore the extent to which differences in engagement to particular AAC technologies result in differences in communication and language learning over time as might be expected.

COMBINATORIAL POLYNOMIALLY COMPUTABLE CHARACTERISTICS OF SUBSTITUTIONS AND THEIR PROPERTIES

2020 ◽  
Vol 7 (2) ◽  
pp. 34-41
Author(s):  
VLADIMIR NIKONOV ◽  
◽  
ANTON ZOBOV ◽  
Keyword(s):  
Mathematical Expectation ◽  
Point Of View ◽  
Small Range ◽  
Computational Point ◽  
Wide Range ◽  
Bijective Function ◽  
The Difference ◽  
Element Base ◽  
Selection Of

The construction and selection of a suitable bijective function, that is, substitution, is now becoming an important applied task, particularly for building block encryption systems. Many articles have suggested using different approaches to determining the quality of substitution, but most of them are highly computationally complex. The solution of this problem will significantly expand the range of methods for constructing and analyzing scheme in information protection systems. The purpose of research is to find easily measurable characteristics of substitutions, allowing to evaluate their quality, and also measures of the proximity of a particular substitutions to a random one, or its distance from it. For this purpose, several characteristics were proposed in this work: difference and polynomial, and their mathematical expectation was found, as well as variance for the difference characteristic. This allows us to make a conclusion about its quality by comparing the result of calculating the characteristic for a particular substitution with the calculated mathematical expectation. From a computational point of view, the thesises of the article are of exceptional interest due to the simplicity of the algorithm for quantifying the quality of bijective function substitutions. By its nature, the operation of calculating the difference characteristic carries out a simple summation of integer terms in a fixed and small range. Such an operation, both in the modern and in the prospective element base, is embedded in the logic of a wide range of functional elements, especially when implementing computational actions in the optical range, or on other carriers related to the field of nanotechnology.

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