scholarly journals Study of the Influence of Helical Milling Parameters on the Quality of Holes in the UNS R56400 Alloy

2020 ◽  
Vol 10 (3) ◽  
pp. 845 ◽  
Author(s):  
Francisco Javier Puerta-Morales ◽  
Jorge Salguero Gomez ◽  
Severo Raul Fernandez-Vidal
Keyword(s):  
Titanium Alloy ◽  
Relevant Information ◽  
Helical Milling ◽  
Future Research ◽  
Kinematic Parameters ◽  
Hole Quality ◽  
Milling Parameters ◽  
Preliminary Study ◽  
Conventional Drilling

Helical milling has been positioned as an alternative to conventional drilling, where the advantages it offers make it very attractive for use on difficult-to-machine alloys such as the titanium alloy UNS R56400. However, the correlation between the indicator of hole quality and the kinematic parameters has rarely been studied. The kinematics are what bring most advantages and that is why it is necessary to know their influence. In this aspect, there are different focuses of problems associated with the complexity of the process kinematics, which makes it necessary to undertake a deeper analysis of the process and to carry out a preliminary study. To address this problem, a DOE (Design of Experiments) is proposed to identify the sensitivity and the main trends of the properties that define the quality holes with respect to the kinematic parameters. At the same time, a nomenclature is proposed to unify and avoid misinterpretations. This study has allowed us to obtain conclusive results that offer very relevant information for future research

scholarly journals ‘A HOARY ANTIQUITY OF UNIMAGINED REMOTENESS’: A Historiography of Archaeological Investigations at the Cheddar Gorge, Somerset, UK.

2018 ◽  
Author(s):  
Katie Davenport-Mackey ◽  
Paul Richard Preston
Keyword(s):  
Relevant Information ◽  
Resource Assessment ◽  
Future Research ◽  
Historical Documents ◽  
Sources Of Information ◽  
Inaccurate Information ◽  
The Past

For the most part, histories of the archaeological discoveries in Cheddar Gorge have been based on anecdotal or oral accounts. Such evidence is unreliable and if accepted uncritically may result in the spreading of inaccurate information and the perpetuation of myths that distort our knowledge of the past and ultimately obfuscate future research. Indeed, most histories of the investigations at Cheddar Gorge have been simple uncritical narratives that fail to evaluate the veracity of sources of information as well as the quality of the archaeological information obtained. Therefore, to verify the claims of archaeological discoveries in Cheddar Gorge, the aims of this paper are to undertake a historiographical analysis of archaeological studies and excavation reports and to undertake a resource assessment of the actual archaeology recovered and recorded. This paper, therefore, not only demonstrates that historical documents can provide archaeologically relevant information about past investigations at Cheddar Gorge, but also outlines a more relevant, verifiable, and unbiased history for use by current and future researchers.

Effect of Drilling Parameters on Hole Quality of Ti-6Al-4V Titanium Alloy in Dry Drilling

2016 ◽  
Vol 880 ◽  
pp. 33-36 ◽  
Author(s):  
Saad Waqar ◽  
Saad Asad ◽  
Shamraiz Ahmad ◽  
Ch Asad Abbas ◽  
Hassan Elahi
Keyword(s):  
Titanium Alloy ◽  
Drill Hole ◽  
Hole Quality ◽  
Machined Surface ◽  
Machine Material ◽  
Dry Drilling ◽  
Drilling Parameters ◽  
Machining Operations ◽  
Exit Burr

In past few decades, a lot of research has been done in the field of machining to improve the quality of machined surface. Out of these machining operations, drilling is widely used in the areas of marine and aerospace for assembly requirements. Titanium alloy Ti-6Al-4V, owing to its vast applications, is regarded as an important material for these industries. Ti-6Al-4V is categorized as difficult to machine material. Based on above stated facts, an experimental study was conducted on the dry drilling of Ti-6Al-4V. The objective of this study was to establish the correlations between drilling parameters such as feed rate and spindle speed, and quality of machined surface which is evaluated in terms of drill hole diameter deviation, exit burr height and surface roughness.

Effect of the performance of physical and non-physical facilities on higher institutional facilities

2018 ◽  
Vol 16 (4) ◽  
pp. 374-386 ◽  
Author(s):  
Isa Abdullahi ◽  
Wan Zahari Wan Yusoff
Keyword(s):  
Structural Equation ◽  
Teaching And Learning ◽  
Influencing Factor ◽  
Relevant Information ◽  
Facility Management ◽  
The Body ◽  
Future Research ◽  
Content Type ◽  
National University

Purpose The role of institutional facilities is of paramount importance to ensure quality of teaching and learning with respect to achieving quality of education in any given higher educational institutions (HEIs). The purpose of this paper is to determine the performance of physical and non-physical facilities of higher institutional facilities. Design/methodology/approach The data were collected from respondents using a closed-end questionnaire. In total, 1,000 questionnaires were administered to students and 735 were returned and valid for analysis. Partial least squares-structural equation modelling was adopted for analysis. Findings It was found that the exogenous constructs [physical facilities (PPE) and non-physical facilities (PNE)] scored 32.7 per cent (R2 = 0.327) of the variance of the facility’s performance. It was also found that the physical facility is the most significant factor that determines facility performance. Research limitations/implications This paper is limited to investigating the performance of physical and non-physical facilities; it is not in any way a measure for the students’ views about other services offered by the institutions. Future research is needed to use relevant information from HEIs’ facilities for validating factors that determine the facility’s performance. Practical implications Physical facility was identified as the most influencing factor that determines the facility performance based on the information provided by respondents. This research should help the facility management department at HEIs when designing the academic facility management. The study will also serve as a yardstick for the Federal Ministry of Education, the National University Commission in academic facility accreditation. This paper contributes to both the body of knowledge in facility management by considering the performance of facilities at HEIs. Originality/value This paper demonstrates the duality of HEIs’ facilities into physical and non-physical facilities and their distinct contribution to the overall facility’s performance.

scholarly journals Does mindfulness intervention improve quality of life in adults with non-malignant chronic pain

2021 ◽  
Author(s):  
◽  
Nikolay Kondratyev
Keyword(s):  
Quality Of Life ◽  
Chronic Pain ◽  
Literature Review ◽  
Well Being ◽  
Relevant Information ◽  
Primary Care Providers ◽  
Future Research ◽  
Care Providers ◽  
The Impact

Chronic pain is a significant problem that negatively affects quality of life resulting in distress, disability, and inappropriate prescription of analgesics. Primary care providers need evidence for non-pharmaceutical tools, such as mindfulness-based intervention, to manage the complexities of chronic pain. The purpose of this integrative literature review is to investigate the impact mindfulness may have on the quality of life of subjects with chronic pain. A background of relevant information is presented regarding chronic pain, quality of life, and mindfulness. Thereafter, a comprehensive search revealed 14 studies in this integrative literature review. Key findings include that there is low to moderate quality evidence that mindfulness improves QOL, especially in the domains of mental well-being. Overall, mindfulness can be an effective tool for individuals that are currently on pharmacological monotherapy. The study concludes with recommendations for future research and practice.

scholarly journals Comparison of conventional drilling and helical milling for hole making in Ti6Al4V titanium alloy under sustainable dry condition

2021 ◽  
Vol 8 ◽  
pp. 12
Author(s):  
Sneharika Akula ◽  
Sadvidya N. Nayak ◽  
Gururaj Bolar ◽  
Vishwanath Managuli
Keyword(s):  
Titanium Alloy ◽  
Thrust Force ◽  
Milling Process ◽  
Helical Milling ◽  
Hole Drilling ◽  
High Temperature Strength ◽  
Drilling Process ◽  
Ti6al4v Titanium Alloy ◽  
Lower Magnitude ◽  
Conventional Drilling

Hole drilling in Ti6Al4V titanium alloy is challenging due to its poor machinability resulting from high-temperature strength and low thermal conductivity. Therefore, an evaluation of the helical milling process is carried out by comparing the thrust force, surface roughness, machining temperature, burr size, and hole diametrical accuracy with the conventional drilling process. The results indicate the advantage of the helical milling in terms of the lower magnitude of thrust force. The holes generated using helical milling displayed a superior surface finish at lower axial feed conditions, while higher axial feed conditions result in chatter due to the tool deformation. Also, the absence of a heat-affected zone (HAZ) under dry helical milling conditions indicates the work surface formation without thermal damage. Besides, a significant reduction in the size of the burrs is noted during helical milling due to lower machining temperature. Analysis of the hole diameter reinforces the capability of the helical milling process for processing H7 quality holes. Consequently, helical milling can be considered a sustainable alternative to mechanical drilling, considering its ability to machine quality holes under dry machining conditions.

Analysis of Tool Wear and Hole Quality During Ultrasonic Assisted Drilling (UAD) of Carbon Fibre Composite (CFC) / Titanium Alloy (Ti6Al4V) Stacks

2015 ◽  
Author(s):  
Aishah Najiah Dahnel ◽  
Helen Ascroft ◽  
Stuart Barnes ◽  
Maximilian Gloger
Keyword(s):  
Titanium Alloy ◽  
Tool Wear ◽  
Fibre Composite ◽  
Optical Microscope ◽  
Hole Quality ◽  
Carbon Fibre Composite ◽  
Outer Skin ◽  
Ultrasonic Assisted ◽  
Thrust Forces ◽  
Conventional Drilling

Carbon Fibre Composite (CFC) and titanium (Ti) alloys have been widely employed in the aerospace industry due to their high strength to weight ratios. For making a military aircraft body, these materials are usually stacked together with titanium alloys serving as the airframe, while CFC is the outer skin. Drilling is often performed in one shot from the CFC outer skin through to the titanium alloy airframe for the purpose of assembling them by mechanical means using rivets, screws, nuts and bolts. Conventional drilling of these CFC/Ti stacks, however, often results in two major issues; rapid tool failure and poor hole quality. This paper considers the potential of employing Ultrasonic Assisted Drilling (UAD) on stack materials in order to improve tool life and hole quality. Experiments comparing conventional drilling and UAD on CFC/Ti6Al4V stack using reground 6.121 mm-diameter TiAlN coated tungsten carbide twist drills are presented. Reground drills were used by way of replicating typical current practice in industry. A constant cutting speed and feed rate of 50 m/min and 0.05 mm/rev, respectively was used in both experiments. During UAD experiments, ultrasonic amplitude and frequency was fixed at 2.6 μm and 42.7 kHz, respectively. A total of 100 holes were drilled in the stacks during each drilling processes (conventional drilling and UAD). Machinability was assessed in terms of thrust forces, tool wear, hole diameter, CFC delamination and titanium burr. Thrust forces were measured using a dynamometer; tool wear was examined using an optical microscope and a Scanning Electron Microscope (SEM); and holes diameter were measured using a bore micrometer. Hole defects; CFC entry delamination was examined and quantified using an optical microscope, while titanium exit burr were investigated using both an optical microscope and a depth gauge. The dominant types of tool wear during drilling of CFC/Ti6Al4V stacks were caused by titanium adhesion/fusion on the cutting edges. In addition, abrasive wear caused by abrading carbon fibres against cutting edges were also observed. Poor hole quality of the stacks included inconsistent diameter of CFC and titanium holes; CFC delamination at the hole entrance and burr formation as the drill exited the titanium. The difference in thrust forces produced by conventional drilling and UAD were minor. It was observed that UAD resulted in less tool wear rate and a reduction of adhered titanium alloy on the cutting edges, more consistent hole diameters and less titanium burr compared to conventional drilling. However, larger CFC delamination was observed during UAD than conventional drilling.

Self-Compassion and Quality of Life in Adults Who Stutter

2020 ◽  
Vol 29 (4) ◽  
pp. 2097-2108
Author(s):  
Robyn L. Croft ◽  
Courtney T. Byrd
Keyword(s):  
Quality Of Life ◽  
Social Connectedness ◽  
The Self ◽  
Future Research ◽  
Self Compassion ◽  
Adults Who Stutter ◽  
And Gender ◽  
Relationship Of ◽  
The Impact

Purpose The purpose of this study was to identify levels of self-compassion in adults who do and do not stutter and to determine whether self-compassion predicts the impact of stuttering on quality of life in adults who stutter. Method Participants included 140 adults who do and do not stutter matched for age and gender. All participants completed the Self-Compassion Scale. Adults who stutter also completed the Overall Assessment of the Speaker's Experience of Stuttering. Data were analyzed for self-compassion differences between and within adults who do and do not stutter and to predict self-compassion on quality of life in adults who stutter. Results Adults who do and do not stutter exhibited no significant differences in total self-compassion, regardless of participant gender. A simple linear regression of the total self-compassion score and total Overall Assessment of the Speaker's Experience of Stuttering score showed a significant, negative linear relationship of self-compassion predicting the impact of stuttering on quality of life. Conclusions Data suggest that higher levels of self-kindness, mindfulness, and social connectedness (i.e., self-compassion) are related to reduced negative reactions to stuttering, an increased participation in daily communication situations, and an improved overall quality of life. Future research should replicate current findings and identify moderators of the self-compassion–quality of life relationship.

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