scholarly journals HYDROGELS THE THREE DIMENSIONAL NETWORKS: A REVIEW

Author(s):  
TRINADHA RAO M. ◽  
PHANINDRA CHVS ◽  
YAMINI M. ◽  
PRASAD C. H.

Hydrogel products constitute polymeric materials as a group, the hydrophilic structure which renders them the capability of holding large amounts of water in their 3-dimensional networks. Extensive employment of those products during a number of commercial and environmental areas of application is taken into account to be of prime importance. Needless to say, natural hydrogels were gradually replaced by synthetic types thanks to their higher water absorption capacity, long service life, and wide sorts of raw chemical resources. Literature on this subject was found to be expanding, especially within the scientific areas of research. However, variety of technical reports publications and handling hydrogel products from the points of view of engineering were examined to overview technological aspects covering this growing the field of research. the first objective of this text is to review the literature concerning classification of hydrogels on different bases, chemical characteristics and physical characteristics of those products, and technical feasibility of their best utilization. It also involved the technologies adopted for hydrogel production along-side process and design implications, optimized conditions, and the block diagrams of the preparation process. Recent forms of hydrogel material generations are also presented in some details that are innovative in nature.

2017 ◽  
Vol 17 (3) ◽  
Author(s):  
Giovanni Calvaruso ◽  
Antonella Perrone

AbstractWe study left-invariant almost paracontact metric structures on arbitrary three-dimensional Lorentzian Lie groups. We obtain a complete classification and description under a natural assumption, which includes relevant classes as normal and almost para-cosymplectic structures, and we investigate geometric properties of these structures.


2005 ◽  
Vol 07 (02) ◽  
pp. 145-165 ◽  
Author(s):  
ALICE FIALOWSKI ◽  
MICHAEL PENKAVA

We consider versal deformations of 0|3-dimensional L∞ algebras, also called strongly homotopy Lie algebras, which correspond precisely to ordinary (non-graded) three-dimensional Lie algebras. The classification of such algebras is well-known, although we shall give a derivation of this classification using an approach of treating them as L∞ algebras. Because the symmetric algebra of a three-dimensional odd vector space contains terms only of exterior degree less than or equal to three, the construction of versal deformations can be carried out completely. We give a characterization of the moduli space of Lie algebras using deformation theory as a guide to understanding the picture.


2018 ◽  
Vol 33 (6) ◽  
pp. 834-853 ◽  
Author(s):  
Reza Moonesi Rad ◽  
Engin Pazarçeviren ◽  
Elif Ece Akgün ◽  
Zafer Evis ◽  
Dilek Keskin ◽  
...  

Every year, many dental restoration methods are carried out in the world and most of them do not succeed. High cost of these restorations and rejection possibility of the implants are main drawbacks. For this reason, a regenerative approach for repairing the damaged dentin-pulp complex or generating a new tissue is needed. In this study, the potential of three-dimensional cellulose acetate/oxidized pullulan/gelatin-based dentin-like constructs containing 10 or 20% bioactive glass nanoparticles was studied to explore their potential for dentin regeneration. Three-dimensional nano biocomposite structures were prepared by freeze-drying/metal mold pressing methods and characterized by in vitro degradation analysis, water absorption capacity and porosity measurements, scanning electron microscopy, in vitro biomineralization analysis. During one-month incubation in phosphate buffered saline solution at 37°C, scaffolds lost about 25–30% of their weight and water absorption capacity gradually decreased with time. Scanning electron microscopy examinations showed that mean diameter of the tubular structures was about 420 µm and the distance between walls of the tubules was around 560 µm. Calcium phosphate precipitates were formed on scaffolds surfaces treated with simulated body fluid, which was enhanced by boron-modified bioactive glass addition. For cell culture studies human dental pulp stem cells were isolated from patient teeth. An improvement in cellular viability was observed for different groups over the incubation period with the highest human dental pulp stem cells viability on B7-20 scaffolds. ICP-OES analysis revealed that concentration of boron ion released from the scaffolds was between 0.2 and 1.1 mM, which was below toxic levels. Alkaline phosphatase activity and intracellular calcium amounts significantly increased 14 days after incubation with highest values in B14-10 group. Von Kossa staining revealed higher levels of mineral deposition in these groups. In this work, results indicated that developed dentin-like constructs are promising for dentin regeneration owing to presence of boron-modified bioactive glass nanoparticles.


2011 ◽  
Vol 31 (1) ◽  
pp. 145
Author(s):  
Alper Osman Öğrenmiş ◽  
Mahmut Ergüt

In this paper, ruled surfaces of type II in a three-dimensional Pseudo-Galilean space are given. By studying its Gauss map and Laplacian operator, we obtain a classification of ruled surfaces of type II in a three-dimensional Pseudo-Galilean space.


2009 ◽  
Vol 20 (02) ◽  
pp. 189-208 ◽  
Author(s):  
MIRJANA DJORIĆ ◽  
LUC VRANCKEN

In this paper, we study certain three-dimensional CR-submanifolds M of the nearly Kähler 6-dimensional sphere S6(1). It is well known that there does not exist a three-dimensional totally geodesic proper CR-submanifold in S6(1). In this paper we obtain a classification of the 3-dimensional CR-submanifolds which are the closest possible to totally geodesic submanifolds, i.e. those that admit a one-dimensional nullity distribution.


2021 ◽  
Vol 77 (1) ◽  
Author(s):  
Ameer Al-Abayechi ◽  
Ágota Figula

AbstractIn this paper we deal with the class $$\mathcal {C}$$ C of decomposable solvable Lie groups having dimension six. We determine those Lie groups in $$\mathcal {C}$$ C and their subgroups which are the multiplication groups Mult(L) and the inner mapping groups Inn(L) for three-dimensional connected simply connected topological loops L. This result completes the classification of the at most 6-dimensional solvable multiplication Lie groups of the loops L. Moreover, we obtain that every at most 3-dimensional connected topological proper loop having a solvable Lie group of dimension at most six as its multiplication group is centrally nilpotent of class two.


Author(s):  
Robert Glaeser ◽  
Thomas Bauer ◽  
David Grano

In transmission electron microscopy, the 3-dimensional structure of an object is usually obtained in one of two ways. For objects which can be included in one specimen, as for example with elements included in freeze- dried whole mounts and examined with a high voltage microscope, stereo pairs can be obtained which exhibit the 3-D structure of the element. For objects which can not be included in one specimen, the 3-D shape is obtained by reconstruction from serial sections. However, without stereo imagery, only detail which remains constant within the thickness of the section can be used in the reconstruction; consequently, the choice is between a low resolution reconstruction using a few thick sections and a better resolution reconstruction using many thin sections, generally a tedious chore. This paper describes an approach to 3-D reconstruction which uses stereo images of serial thick sections to reconstruct an object including detail which changes within the depth of an individual thick section.


Author(s):  
Neil Rowlands ◽  
Jeff Price ◽  
Michael Kersker ◽  
Seichi Suzuki ◽  
Steve Young ◽  
...  

Three-dimensional (3D) microstructure visualization on the electron microscope requires that the sample be tilted to different positions to collect a series of projections. This tilting should be performed rapidly for on-line stereo viewing and precisely for off-line tomographic reconstruction. Usually a projection series is collected using mechanical stage tilt alone. The stereo pairs must be viewed off-line and the 60 to 120 tomographic projections must be aligned with fiduciary markers or digital correlation methods. The delay in viewing stereo pairs and the alignment problems in tomographic reconstruction could be eliminated or improved by tilting the beam if such tilt could be accomplished without image translation.A microscope capable of beam tilt with simultaneous image shift to eliminate tilt-induced translation has been investigated for 3D imaging of thick (1 μm) biologic specimens. By tilting the beam above and through the specimen and bringing it back below the specimen, a brightfield image with a projection angle corresponding to the beam tilt angle can be recorded (Fig. 1a).


2010 ◽  
Vol 3 (2) ◽  
pp. 156-180 ◽  
Author(s):  
Renáta Gregová ◽  
Lívia Körtvélyessy ◽  
Július Zimmermann

Universals Archive (Universal #1926) indicates a universal tendency for sound symbolism in reference to the expression of diminutives and augmentatives. The research ( Štekauer et al. 2009 ) carried out on European languages has not proved the tendency at all. Therefore, our research was extended to cover three language families – Indo-European, Niger-Congo and Austronesian. A three-step analysis examining different aspects of phonetic symbolism was carried out on a core vocabulary of 35 lexical items. A research sample was selected out of 60 languages. The evaluative markers were analyzed according to both phonetic classification of vowels and consonants and Ultan's and Niewenhuis' conclusions on the dominance of palatal and post-alveolar consonants in diminutive markers. Finally, the data obtained in our sample languages was evaluated by means of a three-dimensional model illustrating the place of articulation of the individual segments.


2016 ◽  
Vol 9 (2) ◽  
pp. 120-128
Author(s):  
Haspiadi Haspiadi ◽  
Kurniawaty Kurniawaty

Research of  the utilization solid waste of palm oil fuel ash from boiler as row materials  for manufacturing light concrete brick has been conducted. The main objective of this study is to investigate the potential use solid waste of palm oil fuel ash from palm oil mill boilers as row materials for manufacturing light concrete brick has recently attracted for an alternative environmentally sustainable application. In this study, light concrete brick made with various proportions of palm oil fuel ash from palm oil mill boilers and sand were fabricated and studied under laboratory scales. Percentage of palm oil fuel ash of 0% as a control,  10%, 20%, 30%, 40%, 50%, 60%, replacement  sand, wheras others materials such as Portland cement, lime, gypsum, foaming agent and aluminium with the numbers constant. The quality of light concreate brick   were applied followed by the compressive strength test, density and water absorption capacity. The study discovered that the compressive strength for all composition meet the recommended value to light structural of 6.89 MPa as prescribed in SNI 03-3449-2002. In the same manner density of light concrete brick for all proportion under the maximum density recommended value of 1400 Kg/m3 according to SNI 03-3449-2002. While water absorption capacity of increased by the increasing use of ashes. Therefore, palm oil fuel ash from boiler can be used as raw material for the light concrete brick which is  environmental friendly because using solid waste and also an alternative handling solid waste.ABSTRAKPenelitian pemanfaatan limbah padat abu cangkang dan serat kelapa sawit dari boiler sebagai bahan baku pembuatan bata beton ringan telah dilakukan. Tujuan dari penelitian ini adalah pemanfaatan limbah padat abu boiler berbahan bakar cangkang dan serat sebagai bahan pembuatan bata beton ringan sebagai salah satu alternatif pengelolaan lingkungan yang bekelanjutan. Dalam penelitian ini, bata beton ringan dibuat dengan berbagai komposisi abu boiler dan pasir yang diproduksi dalam  skala laboratorium. Persentase dari abu berturut-turut 0% sebagai kontrol, 10%, 20%, 30%, 40%, 50% dan 60% mensubtitusi pasir, sedangkan bahan lain yaitu semen, kapur, gypsum,  foaming  agent serta aluminium pasta dengan jumlah tetap. Mutu bata beton ringan yang diujikan adalah kuat tekan, bobot jenis dan daya serap air. Hasil penelitian menunjukkan bahwa kuat tekan untuk semua komposisi memenuhi batas minimum yang dipersyaratkan untuk stuktural ringan yaitu 6,89 MPa sesuai SNI 03-3449-2002. Demikian pula bobot jenis dari bata ringan yang dihasilkan masih dibawah dari batas maksimum yang direkomendasikan SNI 03-3449-2002 yaitu maksimal 1400 Kg/m3. Sedangkan daya serap air mengalami kenaikan dengan naiknya jumlah abu yang digunakan . Limbah padat abu boiler berbahan bakar cangkang dan serat sawit dapat dimanfaatkan sebagai bahan baku pembuatan bata beton ringan yang ramah lingkungan dengan memanfaatkan limbah dan menjadi salah satu alternatif pengelolaan limbah. Kata kunci :  Abu cangkang kelapa sawit,  bata beton ringan, bobot jenis,  daya serap air,  limbah,  kuat tekan


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