scholarly journals Directions for increasing conical picks’ durability

2019 ◽  
Vol 2 (1) ◽  
pp. 277-286
Author(s):  
Łukasz Bołoz

Abstract Conical picks are cutting tools used in many branches, in particular in the mining, road construction and building branch. Contact with the excavated face causes their constant wear, which is an unfavorable but unavoidable process. Milling heads of working machines are equipped with several dozen conical picks, and mining in abrasive or hardly accessible rocks can reduce their life to a few hours. It is in the interest of both users and producers to increase their durability, as tools replacement, apart from purchase and logistic costs, results in machine downtimes. In the article various solutions of conical picks, their construction, dimensions and materials used have been discussed. Technical procedures applied to increase the durability of conical picks and their regeneration as well as methods of extending the life of picks working in difficult conditions have been presented. Two author’s methods of extending the life of picks working in difficult conditions, covered by a patent application, have also been presented. The first solution involves ensuring an uninterrupted rotational movement of the pick in the holder. Patent claims include an innovative method of equipping the additional sleeve integrated with the holder with a rotational bearing, which enables a continuous rotation of the pick. The tool equipped with a bearing generates much lower movement resistance than the standard mounting. The holder is designed to mount classic commercial picks. What is important, the pick replacement does not require interfering with the bearing assembly. The second solution concerns the manner of protecting the working part of the pick by means of a special element made of an abrasion resisting material. This element is the pick tip, the geometry of which varies from the commonly applied posts made of sintered carbide. In this solution, the tip has a shape corresponding to the form of conical pick’s wear, which causes that its steel body does not wear. Moreover, there is a possibility of applying a mobile, rotational mounting of the tip to the body.

2020 ◽  
Vol 3 (1) ◽  
pp. 221-230
Author(s):  
Łukasz Bołoz

AbstractMechanical cutting in underground mining faces increasingly difficult challenges. Deteriorating working conditions result in the development of automation and robotization, and the insufficient durability of cutting tools remains a serious problem. In addition to drilling, the technology of cutting provides a huge market for tools. Currently, mainly conical picks are used in the process of cutting. The cutterheads of shearers are equipped with at least several dozen conical picks, which, due to their workability and abrasiveness, sometimes work for merely a few hours. Hence the interest of users and manufacturers in the development of tools with increased durability. The article briefly presents the applied solutions of conical picks, their construction, dimensions and materials used. Attention was paid to the issues related to the protection applied and its marking. A review and analysis of commonly known construction solutions for picks and holders have also been carried out, and proprietary patent pending solutions for the pick and holder have been presented.


Food Industry ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 71-78
Author(s):  
Ekaterina Minnikhanova ◽  
Nataliya Zavorokhina ◽  
Anna Gilina

Abstract The inclusion of polysaccharide thickeners in the recipes of sweet dishes increases the functional reserves of the body, contributes to the preservation of health and the prevention of diseases. The purpose of the research is to study the sensory characteristics of polysaccharides of various nature when combined with food acids, to develop a recipe for a basic mixture of low-calorie meals for public catering. The authors analyzed citric, lactic and succinic acids in combinations with polysaccharides of various nature. Organoleptic tests were evaluated by a touch panel. The organization of the tasting analysis corresponded to GOST ISO 6658-2016; the consistency was determined according to GOST 31986-2012, GOST ISO 11036-2017, GOST ISO 8588-2011. The optimal organoleptic combinations of the presented food acids and complex additives of sweeteners (CDP) were identified, which included aspartame, sodium saccharinate, Sucralose, sweetness coefficient – 340: the mixture with citric acid had a long pleasant aftertaste without foreign tastes and the best taste characteristics. Using the “A-not A” method, we found that the sample with the addition of CDP is identical to the sucrose solution. In the second part of the study, polysaccharides were added to model samples of acids with complex sweeteners; the best sensory characteristics were obtained by model samples consisting of a mixture of low-esterified Apple pectin with lactic acid and KDP. The technology of obtaining a stable elastic jelly using low-esterified Apple pectin has been developed, since the complex mixture of sweeteners and food acids does not have a dehydrating effect. Developed a dry mix recipe that can serve as a basic development, low-calorie sweet products for catering and has a variance of use of lactic and succinic acids, depending on the flavor characteristics of the raw materials used and its corrective ability.


2020 ◽  
Vol 86 ◽  
pp. 285-304
Author(s):  
Emilie Vannier

This paper concerns the architecture of formal burials from the La Tène period in north-western Gaul and southern Britain. The research focuses on the shape and dimensions of sepulchral pits containing inhumed or burnt human remains, on the different materials used for the internal elements, and the external constructions and structures covering, framing, or marking the burials. The study of these data exposes the preferred choices in the funerary architecture of Gallic and British communities during the last five centuries bc. The results reveal different regional funerary groups within three main cross-Channel zones according to the architectural elements of the graves and the main treatments of the body. The distinct characteristics of these groups highlight their common features and relationships with neighbouring areas of the Continental and Atlantic zones.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Erfan Dashtimoghadam ◽  
Farahnaz Fahimipour ◽  
Andrew N. Keith ◽  
Foad Vashahi ◽  
Pavel Popryadukhin ◽  
...  

AbstractCurrent materials used in biomedical devices do not match tissue’s mechanical properties and leach various chemicals into the body. These deficiencies pose significant health risks that are further exacerbated by invasive implantation procedures. Herein, we leverage the brush-like polymer architecture to design and administer minimally invasive injectable elastomers that cure in vivo into leachable-free implants with mechanical properties matching the surrounding tissue. This strategy allows tuning curing time from minutes to hours, which empowers a broad range of biomedical applications from rapid wound sealing to time-intensive reconstructive surgery. These injectable elastomers support in vitro cell proliferation, while also demonstrating in vivo implant integrity with a mild inflammatory response and minimal fibrotic encapsulation.


2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Oleg Riabov

This article deals with the US Cold War cinematographic construction of the Soviet enemy. The researcher focuses on the means of dehumanising the communist enemy, external and internal, by equating it to a machine. The author applies Nick Haslam’s dual model of dehumanization (2006), according to which dehumanization is visible in two main forms: animalistic, by associating members of the out-group with animals, and mechanistic, by associating them with a soulless machine. The materials used consist of US films from the “Long Fifties”, in which Hollywood, equating the enemy to machines, developed three plots: the robotic existence of individuals in a totalitarian society; the transformation of Americans into zombies by communists by means of Soviet science; and the body snatching of Americans by an alien mind, an allegory of a future communist occupation of the USA. The article demonstrates that dehumanization was implemented by directly labeling the representatives of the communist world as robots and by attributing to them a lack of emotions, consciousness, will, individuality, initiative, warmth, love, friendship, creative abilities, and even the ability to smile. Such an image of the enemy implied a moral exclusion, treating them as an inanimate object unworthy of empathy, including in the event of their destruction. The author points out that the use of mechanistic dehumanization was very effective. Essentialization of the differences between “us” and “them” occurred: the symbolic border between them is presented as a boundary between living and nonliving. The image of mortal danger was created: the “Red Machine” is strong and merciless, it cannot be moved to pity, and so it is permissible to destroy it. This image contributed to the legitimation of power: the political opponents of the authorities are represented as internal enemies who are anxious to turn Americans into obedient executors of someone else’s will and to deprive them of humanity. At the same time, the machine also has weaknesses, and it is possible to defeat it: since it is devoid of human creativity, it is clearly inferior to the free human spirit embodied in America.


2020 ◽  
Author(s):  
Erfan Dashtimoghadam ◽  
Farahnaz Fahimipour ◽  
Andrew Keith ◽  
Foad Vashahi ◽  
Pavel Popryadukhin ◽  
...  

Abstract Current materials used in biomedical devices do not match tissue’s mechanical properties and leach various chemicals into the body. These deficiencies pose significant health risks that are further exacerbated by invasive implantation procedures. Herein, we leverage the brush-like polymer architecture to design and administer minimally invasive injectable elastomers that cure in vivo into leachable-free implants with mechanical properties matching the surrounding tissue. This strategy allows tuning curing time from minutes to hours, which empowers a broad range of biomedical applications from rapid wound sealing to time-intensive reconstructive surgery. These injectable elastomers support in vitro cell proliferation, while also demonstrating in vivo implant integrity with a mild inflammatory response and minimal fibrotic encapsulation.


2013 ◽  
Vol 2 (3) ◽  
pp. 136-141
Author(s):  
Prasetyanugraheni Kreshanti ◽  
Siti Handayani ◽  
Kristaninta Bangun ◽  
Melina Tiza

Background: To evaluate two pediatric patients with syndromic craniofacial anomaly that underwent craniofacial reconstructive surgery using resorbable plate-screw systems which have been claimed as biodegradable fixation materials and used in craniofacial reconstructive procedures owing to their advantages such as adequate biomechanical resistance, longer dwelling time, elimination through physiological routes without causing any foreign body reaction and/or significant sequale. Patient and Method: Resorbable plate-screw systems used in 2 patiens for craniofacial reconstructive procedures such as bilateral fronto-orbital advancement and segmental right orbita (four wall box) osteotomy were evaluated as for their efficacy. Result: Adequate fixation was obtained in both patient, but Infection complication was seen in segmental right orbita osteotomy patient that appear localized abcess formation on subciliary incision and fronto medial insicion. After drainage insicion and antibiotic administration for 1 week, the infection was relieved. Summary: Owing to resorbable copolymer which contain a polyester derivate of L- lactidc and glycolic acid are ideal fixation materials used favourably in pediatric craniofacial reconstructive surgery and have further advantages such as adequate biomechanical resistance against distraction and compression forces in the early postoperative period, longer dwelling time and elimination from the body through physiological routes without causing any foreign body reaction.


2019 ◽  
Vol 1 (1) ◽  
pp. 012-018

Medical engineering, as an auspicious conjunction between healthcare practice, biotechnology and materials science, has emerged over time with the aim to improve human’s health. Cornea, an essential part of the eye responsible for most of its optical power, suffers every day due to accidents or various diseases. To avoid complications and overcome limitations of conventional transplantation and other surgical procedures, biomaterials and bioprinting proved beneficial can be used to design optimal devices for corneal implantation. During medical evolution, biopolymers have been used especially in tissue engineering applications, due to their high elasticity and flexibility, adaptable optical properties and tunable microstructure. Natural polymers are well accepted by the body, their offer support for tissue regeneration and, in most cases, they are easy to obtain. Beside natural-derived biopolymers, synthetic polymers can be used in bioprinting to develop performance-enhanced platforms for corneal bioengineering. Bioprinting represents an innovative method to obtain a corneal implant and has the advantage to enable the facile control over some specific properties, such as thickness, color, elasticity or shape.


Author(s):  
Harcharan Singh Ranu

Design of an artificial knee was developed using computer 3-D modeling, the high flexion knee was obtained by using a multi-radii design pattern, The increase of final 20 degrees in flexion was obtained by increasing the condylar radii of curvature. The model of the high flexion knee was developed and one of the models was subjected to finite element modeling and analysis. The compositions of components in the artificial knee were, femoral component and the tibial component were metal, whereas the patellar component and the meniscal insert were made using polyethylene. The metal component used for the analysis in this study was Ti6Al4V and the polyethylene used was UHMWPE. Overall biomaterials chosen were: meniscus (UHMWPE, mass = 0.0183701 kg, volume = 1.97518e-005 m3), tibial component (Ti6Al4V, mass = 0.0584655 kg, volume = 1.32013e-005 m3), femoral component (Ti6Al4V, mass = 0.153122 kg, volume = 3.45742e-005 m3), total artificial assembly (mass = 0.229958 kg, volume = 6.75e-005m3). However, in this design the load had been taken to 10 times the body weight. The weight over single knee is only half the maximum load as the load is shared between the two knee joints. Following were the loading conditions, taking average body weight to be 70Kgs and taking extreme loading conditions of up to 10 times the body weight, i.e. 700Kgs on each of the leg performed the Finite Element Analysis (FEA) over the newly designed knee. The loading was done at an increment of 100 Kgs. The loading conditions and the meshing details for the analysis of the assembly were Jacobian check: 4 points, element size: 0.40735 cm, tolerance: 0.20367 cm, quality: high, number of elements: 80909, number of nodes: 126898. A maximum load of 600 Kgs is optimum for this model. The other components observed linear elastic behavior for the applied loads. Based on these results it was determined that the load bearing capacity of the model were well within the failure levels of the materials used for the analysis. A maximum load of 600 Kgs is optimum for this model. The other components observed linear elastic behavior for the applied loads. Based on these results it was determined that the load bearing capacity of the model were well within the failure levels of the materials used for the analysis. Conclusion drawn from this is that for the first time an innovative new design of an artificial knee joint to suite a segment of some religious population has been developed. This allows them to pray, bend in different positions and squat without too much difficulty.


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