scholarly journals Experimental Investigation of the Crater Caused by Hypervelocity Rod Projectile Impacting on Rocks

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yanyu Qiu ◽  
Songlin Yue ◽  
Mingyang Wang ◽  
Gan Li ◽  
Yihao Cheng ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Impact Crater ◽  
Energy Scale ◽  
Small Scale ◽  
Essential Difference ◽  
Impact Cratering ◽  
Dimensionless Analysis ◽  
Gas Gun ◽  
The Impact ◽  
The Relationship

To investigate the cratering effects of hypervelocity rod projectile impacting on rocks, a two-stage light gas gun was used to carry out 10 groups of small-scale experiments, whose velocity ranges from 1.5 km/s to 4.1 km/s. After each experiment, the morphology and size of the hypervelocity impacting crater were accurately obtained by using a device for image scanning. According to the morphology of the final crater, the impact crater can be divided into crushing area, spallation area, and radial crack area. Based on the experimental results of steel projectile vertical impacting on granite targets, the relationship between the depth and the diameter of the crater is analyzed, i.e., h/D≈0.1∼0.2; it shows that the depth of the crater is much smaller than the diameter of the crater, and the crater seems to be a shallow dish. The relation between the kinetic energy of the projectile and the size of the crater was discussed. With the increase of the projectile kinetic energy, it is uncertain whether the depth of the crater increases, but the volume of the crater will increase. Lastly, dimensionless analysis of the impact crater was carried out. Specifically, the limitations of point source solutions to hypervelocity rod projectile impact cratering have been proved, and there is no essential difference to calculate the final crater by using the energy scale or the momentum scale.

scholarly journals A Preliminary Study on Translational Kinetic Energy Absorption Using Coconut-Fiber (Coir) Sheets as a Potential Impact-Worthy Constituent in Advanced Aerospace Material

2011 ◽  
Vol 471-472 ◽  
pp. 1028-1033 ◽  
Author(s):  
Nuraishah Bazilah Affandi ◽  
Azmin Shakrine Mohd. Rafie ◽  
Shahnor Basri ◽  
Fairuz Izzuddin Romli ◽  
Dayang Laila Abang Abdul Majid ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Energy Absorption ◽  
Natural Fiber ◽  
Small Mass ◽  
Aerospace Material ◽  
Gas Gun ◽  
Preliminary Study ◽  
The Impact ◽  
The Relationship ◽  
Steel Projectiles

Known as “coir”, the fibrous husk of the coconut fruit has potential for integration as a constituent in impact-resisting aerospace materials. As a preliminary study, kinetic energy absorption of this natural fiber is studied prior to further testing, for instance; a non-ballistic surface impacted at high velocity by a small mass is the equivalent mock-up to runway debris. The purpose of this study is to find the relationship between the thickness of the fiber with the kinetic energy absorption. Fabricated fiber panels measuring 10×10×t cm with various thickness are subjected to mild steel projectiles launched by a light gas gun at a constant pressure. The velocity of the projectiles is set to be consistent with the velocity range of typical transport-category aircraft. The impact response of the panels aids in predicting the required amendments where plies of coir sheets are increased to which perforation is impossible. The relationship established from the experimental results is then used to predict the amount of layers required for total translational kinetic energy absorption.

scholarly journals The Impact of Phenological and Artificial Factors on Seed Quality in a Nematode-resistant Pinus densiflora Seed Orchard

2009 ◽  
Vol 58 (1-6) ◽  
pp. 145-152 ◽  
Author(s):  
H. Ozawa ◽  
J. Watanabe ◽  
H. Chen ◽  
K. Isoda ◽  
A. Watanabe
Keyword(s):  
Seed Quality ◽  
Pinus Densiflora ◽  
Seed Orchard ◽  
Small Scale ◽  
Maternal Contribution ◽  
Paternal Parent ◽  
A Minor ◽  
The Impact ◽  
The Relationship ◽  
Seed Resistance

Abstract To clarify the relationship between the impact of phenological and/or artificial factors on seed quality, we measured the numbers of strobili on nematode-resistant Pinus densiflora clones grown in an immature and relatively small scale (700 m2) seed orchard. In addition, we established the clonal identities of all ramets, identified the paternal parent of the seeds, and assessed the resistance of seedlings to nematode infection. We also clarified the quantitative differences of strobili among clones; one clone produced 86.4% and 70.8% of all male strobili and female strobili, respectively. However, given that the total contamination ratio of the orchard was 82.0%, immigrant pollen had a larger impact on the success of actual crossing than phenology. Seedlings with a resistant maternal parent were resistant, even when their paternal parent was from outside the orchard. Two unselected clones were also planted in the seed orchard, one of which was not resistant and was associated with a maternal contribution of 34.7% of all seed stock. These findings suggest that, despite having a large impact on the crossing, immigrant pollen has a minor impact on seed resistance. Conversely, unselected and nonresistant clones have a marked impact on seed resistance. We concluded that artificial factors have larger impact on the seed quality than phenological factors in this orchard and the seeds will be of sufficient quality for supplying the market once nonresistant clones have been removed from the orchard.

scholarly journals Technology-Driven Solutions to Prompt Conversation, Aid Communication and Support Interaction for People With Dementia and Their Caregivers: A Systematic Literature Review

2020 ◽  
Author(s):  
Viktoria Hoel ◽  
Carine Mendom Feunou ◽  
Karin Wolf-Ostermann
Keyword(s):  
Literature Review ◽  
Social Interactions ◽  
Third Party ◽  
Small Scale ◽  
People With Dementia ◽  
Conversation Partner ◽  
Person With Dementia ◽  
The Impact ◽  
The Relationship

Abstract Background The impact of dementia on communication capabilities can result in difficulties in social interactions and between people with dementia and their conversation partner, as initiating and maintaining conversations becomes increasingly challenging. The role of technology in promoting social health and participation for people with dementia is increasing, but the usage on technological devices as a third party in social interactions to enhance communication quality is still in its infancy. The objective of this literature review is to provide a comprehensive description of technology-driven interventions for people with dementia and their conversation partners to enhance communication and facilitate positive social interactions. Methods A systematic search was conducted using PubMed, CINAHL and PsycINFO, where titles and abstracts were screened by two researchers independently. The reference lists of initially identified papers were hand-searched for further relevant studies. Quality appraisal of the included studies was assessed using the Mixed Methods Appraisal Tool.Results Twenty-six papers were included., where the most common technologies to facilitate communication and interactions were tablet-computers (n=11), social robots (n=7) and PCs (n=4). By analyzing the impacts of the device(s) on social interaction and communication, five major themes emerged: i) increased interaction; ii) better understanding of the person with dementia; iii) improved conversational quality; iv) reducing pressure on the conversation partner; and v) a conversational platform.Conclusion While the majority of the included studies are small-scale, they indicate promising findings on the potential of technology in helping dyads to interact in a way that relieves strain on the caregiver, enhances the relationship and engages people with dementia in social activities. Rigorous investigation using standard, comparable measurements is needed to demonstrate the effects of technological solutions, taking on the perspective on caregiving dyads as an entity rather than looking at outcomes for one member of the dyad in isolation.

scholarly journals Customer categorization, relational justice and SME performance in supermarket supply chains

2019 ◽  
Vol 24 (3) ◽  
pp. 417-429 ◽  
Author(s):  
Ricardo Malagueño ◽  
Ismail Gölgeci ◽  
Andrew Fearne
Keyword(s):  
Supply Chains ◽  
Performance Outcomes ◽  
Small Scale ◽  
Least Squares Regression ◽  
Content Type ◽  
Relational Justice ◽  
Supplier Performance ◽  
The Impact ◽  
The Relationship ◽  
Key Customer

Purpose The purpose of this paper is to examine the impact of perceived relational justice on the relationship between key customer categorization and performance of small food and drink producers in supermarket supply chains. Design/methodology/approach Survey data are derived from a sample of (small-scale) suppliers of local and regional food to a large British supermarket. Partial least squares regression analysis was used to test a conceptual framework, which positions relational justice as a mediator in the relationship between key customer categorization and supplier performance, moderated by the length of the relationship. Findings The findings reveal that small suppliers who perceive their treatment by their key customers as fair tend to achieve higher business performance, which supports the hypothesized mediating role of relational justice on supplier performance. However, this research found no evidence to support the hypothesis that this role is moderated by the length of the relationship between the supplier and buyer. Originality/value This paper makes a novel empirical contribution, focusing on performance outcomes for small-scale suppliers in a highly competitive environment (fast-moving consumer goods) with customers (supermarkets) who have significant market power. Accordingly, the paper shows that the way supermarket buyers treat their suppliers matters more for the performance of their suppliers than the very fact that they are key customers.

scholarly journals Effect of Insulation on the Performance of a Rotary Bioreactor for Composting Agricultural Residues

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 315 ◽  
Author(s):  
Fahad Alkoaik ◽  
Ahmed Abdel-Ghany ◽  
Ibrahim Al-Helal ◽  
Mohamed Rashwan ◽  
Ronnel Fulleros ◽  
...  
Keyword(s):  
Heat Loss ◽  
Pilot Scale ◽  
Small Scale ◽  
Plant Residues ◽  
High Quality ◽  
Composting Process ◽  
Weed Seeds ◽  
Rotary Drum ◽  
The Impact ◽  
The Relationship

Rotary drum composters are used to produce high-quality, pathogen-free compost without weed seeds. Insulation is usually applied to small-scale composters to warm up the composted materials and enhance metabolic reactions to produce stable and mature compost within a short time. However, the relationship between the composter size and the heat loss rate is still unclear. In this study, the relationship between the composter size (designated as the ratio of surface area to volume, As/V) and heat loss was analyzed and identified. To show the effect of insulation on the composting performance, two identical rotary drum bioreactors (each of As/V = 9) were used to compost tomato plant residues, one insulated and the other kept without insulation. Results showed that insulation increased the overall resistance against heat loss from the bioreactor from 0.37 (m2 °C W−1) to 1.12 (m2 °C W−1), quickly increasing the compost temperature, and a temperature of 55–67 °C could be achieved and remained for three days. Therefore, mature, stable, well-aged, and high-quality compost was obtained. In the non-insulated bioreactor, the compost temperature did not exceed 37 °C; this caused a decline of microbial activity and the composting process temperature was only in the mesophilic range, leading to a high risk of the existence of weed seeds and pathogens in the final immature compost. Insulation is necessary for laboratory-scale and small pilot-scale bioreactors (As/V ≥ 6), because heat loss is high as As/V is high, whereas it is not necessary for commercial full-scale bioreactors (As/V ≤ 4), because heat loss is minor as As/V is low. For larger pilot-scale bioreactors (As/V: 4–6), insulation cost must be considered when comparing the impact of energy saving on the composting process.

scholarly journals Atmospheric teleconnection patterns and eddy kinetic energy content: wavelet analysis

2004 ◽  
Vol 11 (3) ◽  
pp. 295-301 ◽  
Author(s):  
V. N. Khokhlov ◽  
A. V. Glushkov ◽  
I. A. Tsenenko
Keyword(s):  
Kinetic Energy ◽  
North Atlantic ◽  
Energy Content ◽  
Southern Oscillation ◽  
Eddy Kinetic Energy ◽  
The North ◽  
The North Atlantic ◽  
The Impact ◽  
The Relationship

Abstract. In this paper, we employ a non-decimated wavelet decomposition to analyse long-term variations of the teleconnection pattern monthly indices (the North Atlantic Oscillation and the Southern Oscillation) and the relationship of these variations with eddy kinetic energy contents (KE) in the atmosphere of mid-latitudes and tropics. Major advantage of using this tool is to isolate short- and long-term components of fluctuations. Such analysis allows revealing basic periodic behaviours for the North Atlantic Oscillations (NAO) indices such as the 4-8-year and the natural change of dominant phase. The main results can be posed as follows. First, if the phases of North Atlantic and Southern Oscillations vary synchronously with the 4-8-year period then the relationship between the variations of the NAO indices and the KE contents is the most appreciable. Second, if the NAO phase tends to abrupt changes then the impact of these variations on the eddy kinetic energy contents in both mid-latitudes and tropics is more significant than for the durational dominance of certain phase.

scholarly journals Petrographic Investigation of Target Rock Transformation under High Shock Pressures from the Colônia Impact Crater, Brazil

2017 ◽  
Vol 7 (1) ◽  
pp. 13 ◽  
Author(s):  
Victor F. Velázquez ◽  
Rodrigo F. Lucena ◽  
Jose M. Azevedo Sobrinho ◽  
Alethéa E. Martins Sallun ◽  
William Sallun Filho
Keyword(s):  
Shock Waves ◽  
Impact Crater ◽  
Small Scale ◽  
Impact Melt ◽  
Basement Rocks ◽  
High Shock ◽  
Target Rock ◽  
Deformation Phase ◽  
Deformation Features ◽  
The Impact

The Colônia impact crater, developed on crystalline basement rocks, offers an excellent example of one of the most unique features of the impact process: the effects of shock waves on textural and mineralogical changes of the target rock. The impact melt-bearing impactites were derived essentially from the igneous and metamorphic rocks, including granite, mica schist, granitic gneiss, and quartzite. Investigations using optical microscopy indicate that the effect of shock waves on those lithologies caused a wide variety of deformation features and generation of new materials. The most common features include fluidal textures, unusual rearrangement patterns between grains, recrystallization, decomposition and precipitation of new phases, agglutination of glassy and crystalline spherules, and the mobilized melt formed different types of impact melt particles. These transformations cover processes that may involve a new grain growing at the expense of parental grains of the same species, or crystallization of different mineral types from component-providing grains until a complete textural and compositional change of the target rocks occurs. Small-scale structures in deformed rocks are particularly interesting for exploring elastic-plastic deformation, phase transformations, and generation of impact melt products.

Research of Performance about Ceramic Coating on Aluminum Bumper to Resist Hypervelocity Impact

2013 ◽  
Vol 577-578 ◽  
pp. 629-632
Author(s):  
Gong Shun Guan ◽  
Qiang Bi ◽  
Yu Zhang
Keyword(s):  
Kinetic Energy ◽  
Optimum Design ◽  
Critical Thickness ◽  
Ceramic Coating ◽  
Impact Angle ◽  
Hypervelocity Impact ◽  
Front Side ◽  
Gas Gun ◽  
Whipple Shield ◽  
The Impact

Shield structure based on ceramic coating on aluminum bumper was designed, and a series of hypervelocity impact tests were practiced with a two-stage light gas gun facility. Impact velocities were varied between1.5km/s and 5.0km/s. The diameter of projectiles were 3.97mm and 6.35mm respectively. The impact angle was 0°. The damage of the ceramic coating on aluminum bumper under hypervelocity impact was studied. It was found that the ceramic coating on aluminum bumper could help enhancing the protection performance of shield to resist hypervelocity impact. The results indicated when the ceramic coating is on the front side of aluminum bumper, it was good for comminuting projectile and weakening the kinetic energy of projectile. For a certain aluminum bumper, existing a critical thickness of ceramic coating in which capability of Whipple shield to resist hypervelocity impact is the best. On this basis, the proposal of the optimum design for ceramic coating on aluminum bumper was made.

Impact of Record Keeping on the Growth of Micro- and Small-scale Enterprises: An Analytical Study

2019 ◽  
Vol 46 (2) ◽  
pp. 70-81
Author(s):  
Md Ekbal Hussain Khadim ◽  
Soma Roy Dey Choudhury
Keyword(s):  
Dominant Role ◽  
Pearson Correlation ◽  
Strong Relationship ◽  
Primary Data ◽  
Small Scale ◽  
Record Keeping ◽  
The Status ◽  
Rate Of Failure ◽  
The Impact ◽  
The Relationship

It is well-recognised that micro and small enterprises (MSEs) are acting as specialist and soul of economic growth in India as well as in the world. MSEs are lifeblood of most economies and play a dominant role in the economic development of a country. Research on micro and small business development has shown that the rate of failure in developing countries is higher than in the developed world (Arinaitwe, 2006). The past studies indicate that three out of five businesses fail within the first few months of operation. A study by Peacock (1987) found that the lack of accounting records have led to the failure of these enterprises. This research study investigated the impact of record keeping on the growth of MSEs in the Cachar district of Assam. The objectives of the study were to analyse the relationship between record keeping practice and the growth of MSEs in the study area and to identify the status of record keeping in MSEs in the study area. To achieve these objectives, a sample of 93 entrepreneurs were selected from the targeted population. Primary data were collected by means of structured questionnaire. For data analysis, the study used descriptive statistics, and ‘Pearson’ correlation was used to establish the relationship between the dependent and independent variables. The finding of the study shows that there is a significance positive strong relationship between record keeping practice and growth of the MSEs in the study area.

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