scholarly journals Traditional Gypsum Pavements with Natural Aditives

2022 ◽  
Author(s):  
Belén González Sánchez ◽  
Antonia Navarro ◽  
Judith Ramírez-Casas ◽  
Joan Ramon Rosell
Keyword(s):  
Thermal Conductivity ◽  
Contact Angle ◽  
Natural Products ◽  
Surface Hardness ◽  
The Other ◽  
Structural Elements ◽  
Traditional Architecture ◽  
Ongoing Research ◽  
Material Resources ◽  
Potassium Soap

In traditional architecture, the construction systems used have always been linked to the material resources of the environment. In the areas of extraction of gypsum in the Iberian Peninsula, the use of this material as a conglomerant was not limited to the interior lining of vertical and/or horizontal walls or to interior decorations, as is the case today, but proved to be a very versatile material, which could be used both in structural elements and in finishing elements and decorations. This study shows the preliminary results of an ongoing research on the recovery of traditional gypsum pavements, where three types of traditional gypsum plasters with natural products such as collagen, coconut soap, potassium soap, vegetable oil and marshmallow root were tested. The hygroscopic behaviour of the treated samples has been evaluated from the capillarity water absorption and the contact angle, due to their high hygroscopicity. On the other hand, the density and porosity, surface hardness and thermal conductivity of the samples have also been determined.

Maximizing Heat Transfer Through Joint Fin Systems

2005 ◽  
Vol 128 (2) ◽  
pp. 203-206 ◽  
Author(s):  
A.-R. A. Khaled
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Performance ◽  
Critical Length ◽  
The Other ◽  
Rigid Fixation ◽  
Convection Coefficient ◽  
Heat Transfer Characteristics ◽  
Cold Side ◽  
Transfer Characteristics

Heat transfer through joint fins is modeled and analyzed analytically in this work. The terminology “joint fin systems” is used to refer to extending surfaces that are exposed to two different convective media from its both ends. It is found that heat transfer through joint fins is maximized at certain critical lengths of each portion (the receiver fin portion which faces the hot side and the sender fin portion that faces the cold side of the convective media). The critical length of each portion of joint fins is increased as the convection coefficient of the other fin portion increases. At a certain value of the thermal conductivity of the sender fin portion, the critical length for the receiver fin portion may be reduced while heat transfer is maximized. This value depends on the convection coefficient for both fin portions. Thermal performance of joint fins is increased as both thermal conductivity of the sender fin portion or its convection coefficient increases. This work shows that the design of machine components such as bolts, screws, and others can be improved to achieve favorable heat transfer characteristics in addition to its main functions such as rigid fixation properties.

VISUAL SEMIOLOGY IN ARCHITECTURAL DESIGN

2021 ◽  
Author(s):  
Fatma Nazlı Köksal ◽  
Hasan Doğan
Keyword(s):  
Visual Culture ◽  
Architectural Design ◽  
Communicative Action ◽  
The Other ◽  
Value Systems ◽  
Traditional Architecture ◽  
Traditional Structures ◽  
Social Components ◽  
Cultural Structure ◽  
Physical Components

Beyond being a shelter, houses are such structures which obtain meanings shaped by the influence of culture, particularly reflecting the society’s socio-cultural structure. As a time-khronos and space-topos pattern, the houses reflect the characteristics of the culture or ethnic group which they are part of, while on the other hand, they reflect the images of the individual’s essence as a communicative action. The effect of climate and typology, which are physical components of culture, as well as social components of culture, such as value systems, belief, lifestyle and habits, are cardinal factors in the formation of traditional houses. In this respect, traditional structures are visual representation spaces that narrates their own story, like verbal culture, and they convey their unique codes through visuality. This study, which discusses traditional architecture as a cultural text, aims to reveal traditional Urfa houses through analytical readings, within the context of visual semiology.. The samples selected within the scope of the study will be evaluated according to the context of stylistic features they are part of, such as plan and spatial perspective, the location of the houses, and detections regarding the visual culture will be discussed through the cultural and architectural design approach of Umberto Eco.

Fast and simple fabrication of SiO2/poly(vinylidene fluoride) coated cotton fabrics with asymmetric wettability via a facile spray-coating route

2018 ◽  
Vol 89 (6) ◽  
pp. 1013-1026 ◽  
Author(s):  
Rongrong Yu ◽  
Mingwei Tian ◽  
Lijun Qu ◽  
Shifeng Zhu ◽  
Jianhua Ran ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Contact Angle ◽  
Water Contact Angle ◽  
Vinylidene Fluoride ◽  
Spray Coating ◽  
Cotton Fabrics ◽  
Water Repellent ◽  
Water Contact ◽  
Repellent Property ◽  
Poly Vinylidene Fluoride

Cotton fabrics with hydrophilic-to-hydrophobic asymmetric surfaces are attractive as potential utilizable structures for functional garments. The spray-coating route could be deemed as a fast and simple way to achieve asymmetric surfaces. In this paper, SiO2 nanoparticles with size ∼ 205 nm were synthesized via the modified sol-gel method, and then modified with poly(vinylidene fluoride) (PVDF) to form a hydrophobic surface. The SiO2 nanoparticles modified with PVDF were uniformly deposited on the outer surface of cotton fabric aided with the robust air flow force from the sprayer. The morphology and chemical structures were characterized by scanning electron microscopy, mapping, atomic force microscopy, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The results indicated that SiO2 nanoparticles were evenly deposited on the surface of cotton fibers and stable interfacial interaction occurred between SiO2 and PVDF molecular chains. The existence of SiO2 could increase the roughness of the fabric surface, which could enhance the water-repellent property of the coated fabrics. Furthermore, the water-repellent property and thermal insulation properties were evaluated via the water contact angle and thermal conductivity tests, respectively, and the results showed that 20 wt.% SiO2/PVDF fabric achieved a desirable level of contact angle, 136.6°, which was the largest water contact angle among all the samples, and the lowest thermal conductivity of 0.033 W/mK, resulting from the existence of SiO2 nanoparticles. Such a fast and simple spray-coating strategy could be widely introduced into asymmetric fabric modification, and such asymmetric fabrics with reasonable water-repellent and thermal insulating outer surfaces could act as candidates in the field of functional garments.

scholarly journals Comparison of Multicast Algorithm Evaluation Results in Low and High Multicast Saturation Environments

2019 ◽  
Vol 3 ◽  
pp. 3-7
Author(s):  
Krzysztof Stachowiak ◽  
Piotr Zwierzykowski
Keyword(s):  
Quality Of Service ◽  
Computational Complexity ◽  
Optimization Methods ◽  
The Other ◽  
Ongoing Research ◽  
Mathematical Problems ◽  
Point To Point ◽  
Difficult Challenge ◽  
Entire Network

The multicast quality of service-enabled routing is a computationally challenging task. Despite ongoing research efforts, the associated mathematical problems are still considered to be NP-hard. In certain applications, computational complexity of finding the optimal connection between a set of network devices may be a particularly difficult challenge. For example, connecting a small group of participants of a teleconference is not much more complex than setting up a set of mutual point-to-point connections. On the other hand, satisfying the demand for such services as IPTV, with their receivers constituting the majority of the network, requires applying appropriate optimization methods in order to ensure real system execution. In this paper, algorithms solving this class of problems are considered. The notion of multicast saturation is introduced to measure the amount of multicast participants relative to the entire network, and the efficiency of the analyzed algorithms is evaluated for different saturation degrees.

scholarly journals Solidification of the Sense of Eminency by Distraction of Light and Shadow at Sheikh Lotfollah Mosque

2015 ◽  
Vol 10 (Special-Issue1) ◽  
pp. 208-214
Author(s):  
Moeid Farsa ◽  
Mahdiye Jahri ◽  
Mehdi Alirezai
Keyword(s):  
The Body ◽  
The Other ◽  
Moral Sense ◽  
Natural Light ◽  
Present Survey ◽  
Traditional Architecture ◽  
Physical Presence ◽  
The Mind ◽  
Light And Shadow

Architecture and light are to that extent dependent on each other which body and spirits are.One for living and the other for physical presence in this world needs the other and while light is flown on the body of the space both two perceptible worlds become “ existed “.Since long ago, bright and shimmering materials which remind something living in the mind of individual were respectable and adorable. Being aware of the process of exploitation of sunlight is of importance as much as the process of materials formation or different fundamental forms of construction in order to design. Almost in all religions, light is the symbol of Devine wisdom and the Essene of all beneficence and purities and mobility from darkness to light, was considered as the main objective. Islamic Mosques which are ornamented with light are perfectly able to transmit this divine and moral sense. In such spaces which are lighten up with a shimmering light and by observance of the imprecise shadows of substances and masses, individual starts to complete the pictures in his mind and by such an activity gets in to an ecstasy and as a result a feeling of getting close to the source of existence and reality wakens up inner inside him. The present survey by depending on descriptive-analytic methods, studies light in Islamic and traditional architecture. This paper by case study of Sheikh Lotfollah Mosque, aims to find out whether the presence of light and specifically natural light in architecture might have further meaning rather than brightness, and whether accessing an accurate pattern of application of light is possible or there is basically no compulsion in it ?

Ultrastructural features of the sensori-motor cortex of the primate

1979 ◽  
Vol 285 (1006) ◽  
pp. 123-139 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Motor Cortex ◽  
Thin Layer ◽  
Liquid Helium ◽  
Thermal Insulation ◽  
Solid Surfaces ◽  
The Other ◽  
Experimental Chamber ◽  
Short Discussion ◽  
Inside Wall

cooled to 2°K or lower. Rollin (1936) found that the thermal insulation of vessels containing liquid helium was much worse below than above the A point. He explained his observation by assuming the existence of a thin layer of liquid helium on the inside wall of the connecting tube, and thought it probable that the change in thermal conductivity of this film at the A point gave rise to the anomalous effects observed. As the result of more recent (unpublished) experiments Rollin and Simon* have put forward the other explanation that the film creeps up the tube and evaporates eventually. It is obvious that all these phenomena may have a common explanation and it was the object of the experiments described in this paper and the following paper to investigate the behaviour of He 11 in contact with solid surfaces systematically. The phenomena had to be investigated from various aspects and this made experiments necessary which varied in purpose and character to some extent. For simplicity’s sake we will therefore give, together with the description of each experiment, a short discussion and summarize at the end of the second paper all results in a general discussion on the whole phenomenon. All experiments were carried out in the same cryostat; and for different experiments only the experimental chamber and the experimental arrangement in it were altered.

Tribological Properties of Polyoxymethylene Composites Against Aluminum

2003 ◽  
Vol 125 (3) ◽  
pp. 661-669 ◽  
Author(s):  
Masaya Kurokawa ◽  
Yoshitaka Uchiyama ◽  
Tomoaki Iwai ◽  
Susumu Nagai
Keyword(s):  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
High Surface ◽  
Surface Hardness ◽  
Disk Surface ◽  
Optical Microscope ◽  
Transfer Film ◽  
The Other ◽  
The Coefficient Of Friction

Tribological properties of several kinds of polyoxymethylene (POM) composites were evaluated for the purpose of developing a polymeric tribomaterial especially suited for mating with aluminum parts having low surface hardness. POM composites containing small amounts of silicon carbide (SiC), POM/SiC; those containing a small amount of calcium octacosanonoate besides SiC, POM/SiC/Ca-OCA; and the one blended with 24 wt % of polytetrafluoroethylene, POM/PTFE(24); were injection-molded into pin specimens and their tribological properties were tested by means of a pin-on-disk type wear apparatus using an aluminum (A5056) mating disk in comparison with a 303 stainless steel (SUS303) disk. Evaluation was focused on observation of the sliding surfaces of the pin specimens and the mating disks by a scanning electron microscope and an optical microscope together with the measurement of surface roughness. In the case of mating against a SUS303 disk having high surface hardness, all pin specimens did not roughen the disk surfaces even after long time of rubbing. Only POM/PTFE(24) composite obviously made a transfer film on the disk surface, while the other composites made an extremely thin one on it. POM/SiC(0.1)/Ca-OCA(1) composite, containing SiC 0.1 wt. % and Ca-OCA 1 wt. %, was found to show the lowest coefficient of friction and the lowest wear rate forming extremely thin transfer film on the mating disk. On the other hand, against an A5056 disk which has lower surface hardness than that of SUS303 disk, unfilled POM and POM composites except POM/SiC(0.1)/Ca-OCA(1) composite roughened the disk surfaces. However, the sliding surface of the A5056 disk rubbed with POM/SiC(0.1)/Ca-OCA(1) composite was significantly smoother and that of the pin specimen was also quite smooth in comparison with other pin specimens. Further, when each POM composite was rubbed against the A5056 disk, formation of transfer film was not obvious on the disk surfaces. For POM/SiC(0.1)/Ca-OCA(1) composite, the wear rate was the lowest of all POM composites, and the coefficient of friction was as low level as 60 percent of that of unfilled POM, but slightly higher than that of POM/PTFE(24) composite. For POM/SiC(0.1)/Ca-OCA(1) composite, the nucleating effect of SiC and Ca-OCA, which accelerated the crystallization of POM during its injection molding to form a matrix containing fine spherulites, must have resulted in increasing the toughness of the matrix and lowering the wear rate. Also, the lubricant effect of Ca-OCA should have lowered the coefficient of friction of the same matrix for rubbing against aluminum mating disk. POM/SiC(0.1)/Ca-OCA(1) composite was concluded as an excellent tribomaterial for mating with aluminum parts.

Chemical Defense of Lupins. Mollusc-Repellent Properties of Quinolizidine Alkaloids

1984 ◽  
Vol 39 (6) ◽  
pp. 553-558 ◽  
Author(s):  
Michael Wink
Keyword(s):  
Natural Products ◽  
Lactuca Sativa ◽  
Helix Pomatia ◽  
Free Food ◽  
The Other ◽  
Quinolizidine Alkaloids ◽  
Feeding Response ◽  
Artificial Diets ◽  
Arion Rufus

Polyphagous molluscs such as Helix pomatia and Arion rufus generally do not feed on plants containing alkaloids. Of 19 species tested 10 species were totally avoided, the other 9 species were less attacked than Lactuca sativa, which was readily taken. Plants containing quinolizidine alkaloids were studied in detail. Those species with the α-pyridone alkaloids cytisine and N-methylcytisine were avoided to a higher extent than plants with lupanine as the major alkaloid. Since the repellency observed could be due to other natural products present in the plants besides the alkaloids, the feeding response of Helix pomatia was tested on artificial diets containing quinolizidine alkaloids in various concentrations as the only variable. If the snails had the choice they clearly preferred alkaloid-free food or a diet with only low alkaloid concen­trations. Half-maximal repellency of cytisine is less than 2 mᴍ, of sparteine 1-5 mᴍ, and of lupanine 1-8mᴍ. Since the in vivo concentrations of sparteine, cytisine, and lupanine are equal to or higher than the inhibitory concentrations required it is concluded that quinolizidine alkaloids constitute a potential antimolluscan principle of legumes.

Visual Semiology in Architectural Design

2021 ◽  
Author(s):  
Fatma Nazlı Köksal ◽  
Hasan Doğan
Keyword(s):  
Visual Culture ◽  
Architectural Design ◽  
Communicative Action ◽  
The Other ◽  
Value Systems ◽  
Traditional Architecture ◽  
Traditional Structures ◽  
Social Components ◽  
Cultural Structure ◽  
Physical Components

Beyond being a shelter, houses are such structures which obtain meanings shaped by the influence of culture, particularly reflecting the society’s socio-cultural structure. As a time-khronos and space-topos pattern, the houses reflect the characteristics of the culture or ethnic group which they are part of, while on the other hand, they reflect the images of the individual's essence as a communicative action. The effect of climate and typology, which are physical components of culture, as well as social components of culture, such as value systems, belief, lifestyle and habits, are cardinal factors in the formation of traditional houses. In this respect, traditional structures are visual representation spaces that narrates their own story, like verbal culture, and they convey their unique codes through visuality. This study, which discusses traditional architecture as a cultural text, aims to reveal traditional Urfa houses through analytical readings, within the context of visual semiology. The samples selected within the scope of the study will be evaluated according to the context of stylistic features they are part of, such as plan and spatial perspective, the location of the houses, and detections regarding the visual culture will be discussed through the cultural and architectural design approach of Umberto Eco.

A PEDIATRIC-PSYCHIATRIC VIEWPOINT ON OBESITY

PEDIATRICS ◽  
1957 ◽  
Vol 20 (3) ◽  
pp. 552-556
Author(s):  
Reginald S. Lourie
Keyword(s):  
Point Of View ◽  
The Other ◽  
Structural Elements ◽  
Practical Point ◽  
The Third ◽  
History Of ◽  
Gastric Mucous ◽  
History Of Obesity ◽  
Excessive Quantity ◽  
Layer Concept

FROM the viewpoint of the pediatric psychiatrist, the problems of obesity, as seen clinically, can be thought of as having three layers. The first is constitutional, better described as physiologic, which may be broken down into genetic and structural elements. The second is psychologic, consisting of the values that food intake or the obesity itself come to have. The third layer is made of the cultural and social reactions to food and fat. These attitudes encountered inside and outside the home intermesh in their effects with the physiologic and psychologic levels. These, in turn, are also interwoven, until one cannot separate one layer from the other. However, when individual cases are scrutinized they reveal the pathology at one layer or the other to predominate and indicate where efforts to modify the abnormality might best be directed. Incidentally, the same levels operate on the other side of the coin, anorexia. From the practical point of view, let us consider the natural history of obesity and the clinical varieties one sees in practice, and let us see how the three-layer concept fits. First, as pointed out by Gordon, there is a tendency to be complacent or even pleased with obese infants. At level one, the physiologic, such constitutional factors as those present in the neonate born with an excessive quantity of pepsinogen secreted by the gastric mucous membrane could have the effect of producing as Mirsky points out, a relatively intense or even continuous hunger, and make greater demands on its mother for nursing.

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