Influence of the parameters of deforming cutting on the features of the resulting slotted filter structures

Introduction. Slot filters are in demand in petrochemical, machine-building, food, mining and other industries. DC is an edge cutting machining method based on undercutting and plastic deformation of the workpiece’s surface layer without its removal in the form of chip. DC stands out from the other slot structure forming methods for its capability of obtaining fine filters (slot width upwards of 20 µm) while maintaining relatively high productivity rate and being waste-free. Nevertheless, patterns of through slots cutting by means of DC had virtually not been investigated previously. The purpose of the work is to establish the influence of the main parameters of deformational cutting, namely feed and depth of cut, on features of through slots obtained, as well as identifying combinations of parameters that ensure the production of structures suitable for filtration. Method of investigation consisted of experiments on through-cutting of corrugations stamped on copper strips and a visual analysis of the structures obtained. Cutting through the corrugations by DC was conducted on a lathe while using a special attachment – a barrel which workpiece corrugated strips were wrapped around and fixed on with tension. Results and discussion. The resulting typical structures obtained under different combinations of depth of cut and feed are systemized and divided into the following groups: “0” – the absence of the through cut; “1” – uniform slots; “2” – “twinning” (pairwise convergence of slot walls), “3” – stripping of every second slot wall; “4” – non-regular or complete stripping of slot walls; “5” – uniform slots with a continuous burr (“skirt”) formed along the slot row on the internal side of the corrugation; “6” – uniform slots with a “skirt” opened incompletely. In the range of feeds 0.2 ... 0.4 mm/rev with increasing cutting depth, there is a transition from structures of group “1” to structures of group “2”, and the greater the feed, the greater the maximum depth of cut, at which uniform slots remain. Group “1” is assigned to the area of structures suitable for filtration applications, although it is characterized by the formation of individual burrs on the inner side of each slot. At lower feeds (up to 0.2 mm/rev) with further increase of the depth of cut another group of structures potentially suitable for filtering purposes is reached: groups “5” and “6”. With the “skirt” formed, individual burrs next to each slots are absent, and the shape of slots is cleaner. With a decrease in feed, the width of the resulting slots decreases. The least tool feed value, at which uniform slots are obtained, is 0.05 mm/rev which corresponds to 19 µm slot width. Establishing the causes of “twinning” and the formation of “skirts” requires further investigation.

Development of a Dust Respirator by Improving the Half Mask Frame Design

Protective efficiency of filtering dust respirators depends on the properties of filter materials from which filters are made and the structure of a half mask frame, which influences how tightly the respirator fits the face. The conducted studies on the “Lepestok 40” dust respirator revealed a large air leakage through the gaps occurring along the obturation strip. Therefore, the purpose of the study is to develop a dust respirator to provide high level of protection and usability by improving the half mask frame design. A scheme for designing a dust respirator: analysis of operating conditions for the dust respirator; facial anthropometric measurements of potential users; designing a 3D model of half mask frame; laboratory testing of the protective properties of the product. A distinctive feature of this approach is considering the facial anthropometric dimensions of employees of a particular enterprise, standard sizes formation of 3D facial models, which is the basis for designing a half mask frame for dust respirator. A new half mask frame design for dust respirator with a variable geometry of fitting to the face surface has been developed, due to special attachment points that allow changing its size according to the anthropometric dimensions of user’s face.

The Neighbourhood as Home Away from Home?

Home, as a special attachment to (and appropriation over) place, can also be cultivated in the public urban space, under certain conditions that we explore through a case study in Rinkeby, Stockholm. This article analyses various forms of homemaking in the public among the Somali-Swedes who live there. It shows how, in the case of vulnerable immigrants, a neighbourhood feels like home insofar as it facilitates a continuity with their past ways of living, sensuous connections with a shared ‘Somaliness’, reproduction of transnational ties, and protection from the sense of being ‘otherised’ that often creeps among them. However, homemaking in the public is ridden with contradictions and dilemmas, including those of self-segregation. The grassroots negotiation of a sense of home along these lines invites a novel approach into the everyday lived experience of diverse neighbourhoods in European majority-minority cities.

Maja Smrekar: K-9_topology

K-9_topology, a unit of four art projects created by Maja Smrekar, deals with relevant problems of contemporary society. The cohesive thread which serves as a link between the dramaturgy of every single project is a state of becoming: becoming-animal, becoming-Other. It deals with Deleuzian idea of desubjectivation, social constructs of humanity and interspecies interaction. The basis of her artistic narrative is her own background and special attachment to dogs, which perform as the main actors of K-9_topology. Her projects are an answer to the hopeless state of the Anthropocene. The article aims to deepen the discussion, brought by Maja Smrekar.

Reproductive biology and ecology of the boreoatlantic armhook squid Gonatus fabricii (Cephalopoda: Gonatidae)

The squid Gonatus fabricii (Lichtenstein, 1818) is the most abundant pelagic cephalopod in the Arctic and the only squid to spend all of its life cycle in this region. Despite being highly abundant, its reproductive biology remains poorly known, and data on large maturing and mature specimens are especially rare. This study, based on extensive material (51 large specimens and >35,000 specimens in all), fills major gaps in the knowledge of the reproductive biology and ecology of G. fabricii. The fecundity of females ranged from 8,862 to 16,200 oocytes, with mature and late maturing specimens having between 8,862 to c. 10,000 and 11,402 oocytes, respectively. Oogenesis was synchronous, and oocyte resorption was observed; resorbed oocytes constituted up to 23.5% of fecundity. Between two to five ripe oocytes were observed, and these were 4.0–5.5 mm in diameter (maximum dimension). Males possessed between 77 and 257 spermatophores (length = 5.8–10.8 mm). Spermatophores were characterized by a cement body with well-developed collar and discs at the oral end, an ejaculatory apparatus longer than the cement body and the lack of a tapered, sharp tip to the cement body. Spermatophore size showed a uniform increase in relation to increasing male size. In newer spermatophores, the length, width and volume of the seminal reservoir also increased. Females possessed between 62 and 84 spermatangia (length = 1.8–2.6 mm); the spermatangia were present on the buccal membranes and lacked special attachment structures. Seminal receptacles were not found on the buccal membranes of females. Our findings are consistent with the hypothesis of geographically restricted spawning in G. fabricii. The study found evidence for one new breeding area in south-eastern Greenland. No differences in sizes at maturity were found between the breeding areas. Such geographically localized reproduction is relatively common in non-deep-water squids, but is much less common in deep-water squids. Localized reproduction may be especially important for G. fabricii because increased food availability in the epipelagic layers would likely increase the survival of epipelagic juveniles, with surface currents potentially aiding in their dispersal.

The Use of a Special Stereoscopic Microscope Attachment for the Sieve Analysis of Aggregate in Concrete

The article proposes an innovative technique that allows relatively easy distinction of sand and aggregate particles on the surface image of a concrete specimen. The concept of the proposed approach involves the use of a new method of illuminating carefully polished surfaces of specimens. This is possible owing to a special attachment mounted on the lens of a stereoscopic microscope. The obtained digital image of the specimen, after being converted into a binary image, was subjected to a standard numerical analysis to determine the parameters characterizing the aggregate, i.e., particle size distribution (grading curve), maximum dimension, and shape. Two application examples are presented for analysing sand particle size and for determining the cement paste content in the concrete. The results obtained with the proposed technique were very promising and offer great potential for its practical implementation.

Измерение показателя экстинкции диэлектрических пленок на основе спектроскопии нарушенного полного внутреннего отражения

Various methods of measuring the coefficient of light attenuation in optical coatings are considered. It is shown that the dimensionless extinction index of a coating made of a weakly absorbing film-forming material can be measured using a special attachment based on a parallelepiped-shaped optical prism. Parameters of the proposed attachment are calculated so that it could be arranged inside standard spectrophotometers.

The new sponge species Amphoriscus pedunculatus (Porifera, Calcarea)

Amphoriscus is a widespread genus with 17 species. A new species was found in SE Brazil and it represents the second species of this genus in Brazilian waters. Amphoriscus pedunculatus sp. nov. has a special structure, a peduncle, to attach to the substrate. Special attachment structures are not very common in the class Calcarea but this is the third species of the genus with a peduncle. Besides peduncle, another attachment structure found in some species of Amphoriscus is the root-tuft, an attachment structure composed of diactines and anchor-like triactines or tetractines. The evolution of these attachment structures in Amphoriscus is not known but they have also been found out of this genus, suggesting that these structures appeared several times during the evolution of Calcarea or that species currently classified in different genera are in fact congeneric.

ʿAṭṭār’s Taḏkirat al-awliyāʾ and Jāmī’s Nafaḥāt al-uns

This article presents two famous collections of the lives of saints: ʿAṭṭār’sTaḏkirat al-awliyāʾand Jāmī’sNafaḥāt al-uns. Every collection of the lives of saints shares the common tradition of Arabic-language works. Indeed, Hujvīrī’sKašf al-maḥjūband Anṣārī’sṬabaqāt al-ṣūfiyyahensured the transition with Sufi literature written in Arabic. However, theTaḏkirat al-awliyāʾis the first truly original work in Persian. ʿAṭṭār and Jāmī sought to make known to their respective communities of belief the words and deeds of spiritual masters, but they did so in two different ways. ʿAṭṭār chose a limited corpus of saints that, in his eyes, represented the primary movements of the first centuries of Sufism. Jāmī instead favoured exhaustiveness, amassing a great number of biographies, especially on the shaykhs of the Naqshbandi order. While Jāmī conveyed the paths of saintliness in accordance with the religious orthodoxy of his order, ʿAṭṭār showed a special attachment to the ecstatic masters. TheTaḏkirat al-awliyāʾandNafaḥāt al-unsthus represent two different ways of commemorating the memory of the spiritual masters who embodied the mystical thought of Islam.

The Experimental Determination of One-Axial Tensile Strength of the Textile Reinforced Concrete

This article deals with experimental testing of the textile reinforced concrete samples. The main topic of this article is determination ultimate tensile strength of the textile reinforced concrete. The testing samples were in form “dogbone” for good fixing in testing machine. There are 12 samples totally in experimental program. One type cement matrix and three types (difference in their weight 125 g/m2, 275 g/m2 and 500 g/m2) glass textile reinforcement were used for the production of samples. The textile reinforcement is made of alkali-resistant glass fibres. Three samples were made of cement matrix and nine samples were made of cement matrix reinforced textile reinforcement (three of each type of reinforcement). The samples were tested in special attachment in one-axial tensile. Experimental tests were controlled by speed of rate of deformation (0.0005 m/min). The textile reinforcement has very good influence to behaviour of the textile reinforced concrete in tensile stress.