RP-181: Formulation of Standard Quadratic Congruence of Even Composite Modulus modulo an Even Prime Raised to the Power n

The paper presented here, is a standard quadratic congruence of composite modulus, studied rigorously and found the formulation incomplete. It was partially formulated by the earlier mathematicians. The present authors realised that the earlier formulation need a completion and a reformulation of the solutions is done along with two more results. The author considered the problem for reformulation, studied and reformulated the solutions completely. A partial formulation is found in a books of Number Theory by Zuckerman at el. There the formulation is only for an odd positive integer but nothing is said about even positive integer. The authors have provided a complete formulation of the said quadratic congruence and presented here. Keywords: Composite Modulus, Quadratic Congruence, Reformulation.

Formation of porosity during degradation of basalt-plastic materials in the arctic conditions

The formation of open porosity in reinforcement made of basalt-plastic composite materials is experimentally investigated during testing in the arctic conditions. A statistical model of the formation of porosity during degradation of a composite material with basalt reinforcing fibers is proposed. Keywords: composite materials, climatic tests, porosity, statistical modeling, Markov chain. [email protected]

Reinforced composites with 3D fabric structures

An overview of developments in the creation and production of composites with reinforced fabric structures is presented. The advantages of using fabric reinforcing materials intertwined in a special way into a single structure are shown. Keywords: composite material, fabric material, reinforcement, preform. [email protected], [email protected]

Composite Resin Crown Restoration on Microdontia Maxillary Lateralis Incisor (Case Report)

Microdontia is a tooth size disorder that is smaller than normal teeth. It can cause diastemawith the adjacent tooth. This condition can interfere with the patient’s self-confidence. One of thetreatment choices for microdontia is jacket crown restoration. It provides an ideal anatomicalshape so that fulfills the aesthetic function of the teeth. The current case report aims to describethe treatment of microdontia maxillary right lateral incisors. A composite resin jacket crown waschosen for the treatment. The work steps are included preparation of the crown, impression forthe working model, color matching of the jacket crown, try-in, and insertion of the compositeresin jacket crown. Subjective and objective evaluation a week post cementation showed that thejacket crown treatment, in this case, was successfully done. In conclusion, composite resin jacketcrown restoration on microdontic maxillary lateral incisors using indirect restorations in theform of composite resin jacket crowns showed good results. Keywords: composite resin; jacket crown; microdontia; tooth anomaly

MÉTODOS DE NORMALIZAÇÃO, PONDERAÇÃO E AGREGAÇÃO NA FORMAÇÃO DE (SUB)ÍNDICE DE SUSTENTABILIDADE

The structuring of a sustainability index requires a transparent and reliable process, so that its results are the closest to reality and consistent. This study aimed at a critical analysis of the process of structural elaboration of the (sub) sustainability indexes, comparing its main disadvantages and advantages. The methodology used focuses on the qualitative through the technique of systematic literature review and snowballing. The keywords (composite indicators, index, sustainability, aggregation, normalization, advantages and disadvantages) have been inserted into the Google Scholar, Science Direct, Springer Link and Wiley Online Library search directories. The main results show that the techniques used in the process of standardization, weighting and aggregation of a set of data in a sustainability index present indifferent weaknesses and limitations. In addition, the multicriteria aggregation techniques cover qualitative, quantitative data and their uncertainties, but they do not eliminate the weaknesses and limitations of structuring the sustainability index. Thus, they tend to be more suitable, but do not guarantee that the index generated reflect the complexity of the reality of the system that has been reduced. The theoretical and practical contributions of this study are related to the choices of methods and techniques in structuring the (sub) sustainability index, since even with the choice of the most adequate ones in their elaboration, they do not eliminate their fragilities and limitations. The originality of the study is the combination of the main methods and techniques of elaborating a (sub) sustainability index in a single document, in the Portuguese language.

Structural factors of deformation and failure of metal-matrix composites from "ВТ6" alloy obtained under low-temperature superplasticity

Possibilities of obtaining strong metal-matrix composites by pressure welding at low temperatures are considered. The nature and failure mechanism of the composite are studied. It is established that the strength of the composite obtained at a temperature of 700 °C can exceed the strength of the composite obtained at a temperature of 900 °C. Keywords: composite, pressure welding, solid-phase joint, titanium alloy, nanostructure, strength, plasticity, mechanical properties. [email protected]

Production of Composite Materials By the Powder Metallurgy Method from the Powder Manufactured from Wastes of Mechanical Treatment of Ingots of Alloys VT-22

This study considers the preparation of new composite materials based on VT-22 titanium alloy powder made from waste from machining ingots by plasma spraying. Two composite compositions were selected for the study: 1 - 65% VT-22 + 30% PTM-1 + 5% N70Y30 and 2 - 70% VT-22 + 25% PTM-1 + 5% PMS. The structure and microstructure of the samples were studied, and X-ray phase analysis was carried out. Materials with a homogeneous fine structure were obtained by cold pressing followed by sintering. The samples have the structure of the VT-22 alloy but have a hardness higher than that of the starting material. Keywords: Composite materials, composite pressing, titanium alloy powders, additive powders

SINTESIS PAPAN KOMPOSIT BERBAHAN DASAR SERAT SABUT KELAPA DAN SERAT BUAH KETAPANG DENGAN MATRIK PVAc

ABSTRAKSintesis komposit mengggunakan campuran serat sabut kelapa dan serat buah ketapang dengan matrik Polyvinil Acetat (PVAc) telah berhasil dilakukan. Sampel tersebut dibuat dengan variasi komposisi fraksi volume serat sabut kelapa dan serat buah ketapang yaitu (0:100), (30:70), (40:60), (50:50), (60:40), (70:30) dan (100:0)%. Perbandingan fraksi volume campuran serat alami dan matrik polyvinyl Acetat (PVAc) yang dibuat yaitu (70:30)%. Pembuatan sampel diawali dengan pengambilan serat sabut kelapa dan buah ketapang, penjemuran dan pemotongan, kemudian pencampuran serat sabut kelapa dan serat buah ketapang dengan matriks PVAc, pencetakan komposit dengan alat cetak tekan dan penjemuran. Sampel yang sudah jadi selanjutnya diuji fisiknya dengan cara menentukan nilai massa jenis dan kadar air sampel untuk melihat kualitas sampel. Hasil penelitian menunjukan bahwa secara keseluruhan sampel telihat homogen, massa jenis sampel berkisar antara 0,52- 0,72 gram/cm3 dan nilai kadar air berkisar antara 10,05- 12,89%. Hal ini berarti bahwa sampel komposit telah memenuhi kriteria SNI 03-02105-2006 dan termasuk pada katagori berkerapatan sedang. Kata kunci: komposit; serat sabut kelapa; serat buah ketapang; PVAc. ABSTRACTSynthesis using a mixture of Coconut coir fiber and Terminalia catappa fruit fiber with the Polyvinyl Acetate (PVAc) matrix has been successfully carried out. The samples were made with variations in the composition of the volume fraction of Coconut coir fiber and Terminalia catappa fruit fiber, namely (0: 100), (30:70), (40:60), (50:50), (60:40), (70:30) ) and (100: 0)%. The ratio of the volume fraction of the mixture of natural fibers and the polyvinyl acetate (PVAc) matrix made was (70:30)%. The sample production begins with taking Coconut coir and Terminalia catappa fruit, drying and cutting, then mixing coconut coir and Terminalia catappa fruit fiber with a PVAc matrix, molding the composites using a press printing tool and drying. The finished sample is then physically tested by determining the density value and moisture content of the sample to see the quality of the sample. The results showed that the overall sample looked homogeneous, the density of the sample ranged from 0.52 to 0.72 grams/cm3 and the moisture content ranged from 10.05 to 12.89%. This means that the composite sample has met the SNI 03-02105-2006 criteria and is included in the medium density category. Keywords: composite; coconut coir fiber; terminalia catappa fruit fiber; PVAc.

Unification of instrumental units in the position of mechanical processing of alloys with directional crystallization of eutecnic structures on multi"stream automatic lines

Optimization of machining of parts made of alloys with directed crystallization of eutectic structures by instrumental units on a multi-stream automatic line consisting of one-way automatic machines is proposed. Keywords composite material, eutectic structure, automatic line, tool block, machining. [email protected]

Synthesis of Bi4Ti3O12/TiO2 Composite using Sonication Method

Composite Bi4Ti3O12/TiO2 heterojunction photocatalyst has been prepared by sonication methods. The heterojunction material Bi4Ti3O12/TiO2 was synthesized using an ultrasonic cleaning bath for 4 hours, by mixing Bi4Ti3O12 and TiO2 with variations in the comparison of mol 1:1, 1:2, 1:4 and 1:6. Characterization with XRD showed heterojunction material consisting of Bi4Ti3O12, anatase, rutile, and Bi12TiO20. The surface was observed by SEM which showed the morphology of Bi4Ti3O12/TiO2 were spherical TiO2 and plate-like Bi4Ti3O12. The band gap energy of heterojunction material with a variation in mol Bi4Ti3O12: TiO2 of 1:1, 1:2, 1:4 and 1:6 are 3.09; 3.10; 3.15; and 3.16 eV respectively. The all of band gap energy is lower than the band gap energy of TiO2 anatase and higher than the band gap energy of Bi4Ti3O12.Keywords: composite photocatalyst, heterojunction, sonochemical, Bi4Ti3O12, TiO2.