scholarly journals Influence of chloramine-T disinfection on elastomeric impression stability

2018 ◽  
Vol 12 (02) ◽  
pp. 232-236 ◽  
Author(s):  
Ricardo Danil Guiraldo ◽  
Sandrine Bittencourt Berger ◽  
Marilia Franco Punhagui ◽  
Thais Staut Moretto ◽  
Murilo Baena Lopes ◽  
...  
Keyword(s):  
Descriptive Analysis ◽  
Dental Materials ◽  
Optical Microscope ◽  
Scanning Tunneling ◽  
Mean Values ◽  
The Matrix ◽  
Disinfection Procedure ◽  
Chloramine T ◽  
Materials Used ◽  
The Stability

ABSTRACT Objective: The aim of this study was to evaluate the stability of elastomer through detail reproduction and its dimensional stability (DS) after disinfection with 0.2% chloramine-T. Materials and Methods: The elastomeric impression dental materials used in this study were polydimethylsiloxane (Oranwash L), polyvinyl siloxane (Express), polysulfide (Permlastic), and polyether (Impregum Soft). The entire press procedure was performed on a matrix in accordance with the ISO 4823. Detail reproduction was analyzed using an optical microscope (Stereozoom Microscope) over the 20-μm line with 25 mm of length at a magnification of ×4. DS was measured using an optical microscope (Scanning Tunneling Microscope) by subtracting the distance between the lines X and X’ over the 20-μm line on the matrix (DM) from the distance between the lines on the impression material (DI) divided by DM and multiplied by 100 establishing the equation: DS = ([DI – DM]/DM) ×100; then, 100% was added to the results of the equation. The detail reproduction values were subsequently subjected to descriptive analysis by percentage (%), and the DS values (%) were submitted to Kolmogorov–Smirnov test, two-way ANOVA (material × disinfectant), and Tukey’s test (α = 0.05). Results: All elastomeric impression materials showed 100% of detail reproduction, regardless of the disinfection procedure. Polysulfide (not disinfected) and polysulfide and polydimethylsiloxane (after disinfection with 0.2% chloramine-T) showed the smaller mean values of DS. Conclusion: According to the stability properties analyzed, chloramine-T can be used for disinfection of elastomer molds.

The Effect of Ti-Zr Deoxidation on the Mechanical Properties of High Strength Low Alloy Steels

2010 ◽  
Vol 146-147 ◽  
pp. 1878-1884 ◽  
Author(s):  
Wei Yu Lu ◽  
Ling Dong Meng ◽  
Hong Hong Wang ◽  
Dao Yuan Wang ◽  
Yong Kuan Yao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Impact Toughness ◽  
High Strength ◽  
Optical Microscope ◽  
Low Alloy Steels ◽  
X Ray ◽  
The Matrix ◽  
Alloy Steels ◽  
The Stability

The uniformity of the mechanical properties, especially elongation and impact toughness, were compared between steel A, which was deoxidized with Ti-Zr, and steel B, which was deoxidized with Al. Microstructural observations, energy dispersive X-ray spectroscopy and X-ray diffraction analyses were conducted using an optical microscope, a scanning electron microscope and a transmission electron microscope, respectively. Results showed that sub-micron and nano-sized complex oxides were obtained by the combined deoxidation of Ti-Zr. The stability of the mechanical properties of steel A was better than that of steel B. The elongation and impact toughness of steel A were enhanced relative to those of steel B. This was attributed to spheroidization and the dispersed distribution of MnS inclusions in the matrix of steel A.

scholarly journals Surface detail reproduction and dimensional accuracy of stone models: influence of disinfectant solutions and alginate impression materials

2012 ◽  
Vol 23 (4) ◽  
pp. 417-421 ◽  
Author(s):  
Ricardo Danil Guiraldo ◽  
Thaís Teixeira Borsato ◽  
Sandrine Bittencourt Berger ◽  
Murilo Baena Lopes ◽  
Alcides Gonini-Jr ◽  
...  
Keyword(s):  
Sodium Hypochlorite ◽  
Dimensional Accuracy ◽  
Chlorhexidine Digluconate ◽  
Mean Values ◽  
Impression Materials ◽  
Significant Difference ◽  
Disinfection Procedure ◽  
The Mean ◽  
Surface Detail ◽  
Materials Used

This study compared the surface detail reproduction and dimensional accuracy of stone models obtained from molds disinfected with 2% sodium hypochlorite, 2% chlorhexidine digluconate or 0.2% peracetic acid to models produced using molds which were not disinfected, with 3 alginate materials (Cavex ColorChange, Hydrogum 5 and Jeltrate Plus). The molds were prepared over matrix containing 20-, 50-, and 75-µm lines, performed under pressure with perforated metal tray. The molds were removed following gelation and either disinfected (using one of the solutions by spraying followed by storage in closed jars for 15 min) or not disinfected. The samples were divided into 12 groups (n=5). Molds were filled with dental gypsum Durone IV and 1 h after the start of the stone mixing the models were separated from the tray. Surface detail reproduction and dimensional accuracy were evaluated using optical microscopy on the 50-µm line with 25 mm in length, in accordance with the ISO 1563 standard. The dimensional accuracy results (%) were subjected to ANOVA. The 50 µm-line was completely reproduced by all alginate impression materials regardless of the disinfection procedure. There was no statistically significant difference in the mean values of dimensional accuracy in combinations between disinfectant procedure and alginate impression material (p=0.2130) or for independent factors. The disinfectant solutions and alginate materials used in this study are no factors of choice regarding the surface detail reproduction and dimensional accuracy of stone models.

scholarly journals Experimental and Numerical Analysis of Mold Filling in Rotational Molding

2021 ◽  
Vol 5 (11) ◽  
pp. 289
Author(s):  
Jonas Nieschlag ◽  
Julian Seuffert ◽  
Daniel Strack ◽  
Marco Friedmann ◽  
Luise Kärger ◽  
...  
Keyword(s):  
Capacitive Sensor ◽  
Mold Filling ◽  
Maximum Deviation ◽  
Rotational Molding ◽  
Molding Process ◽  
Average Deviation ◽  
Mean Values ◽  
The Matrix ◽  
Materials Used ◽  
Filling Simulation

This work focuses on the development of a numerical mold filling simulation for the rotational molding process. In the rotational molding process, a dry fiber preform is placed in a mold and impregnated with a thermoset matrix under rotation. Additionally, metallic load introduction elements can be inserted into the mold and joined with co-curing or form-fit, resulting in hybrid drive shafts or tie rods. The numerical model can be used to simulate the impregnation of the preform. Based on the resin transfer molding process, an OpenFOAM solver is extended for the rotational molding process. Permeability, kinetic and curing models are selected and adapted to the materials used. A wireless measurement solution with a capacitive sensor is developed to validate the model. Comparisons between measurements and numerically calculated impregnation times to reach the capacitive sensor with the matrix show good quality of the developed model. The average deviation between calculated result and measured mean values in the experiment is 43.8% the maximum deviation is 65.8% . The model can therefore be used to predict the impregnation progress and the curing state.

EVALUATION OF TRIBOTECHNICAL PROPERTIES OF THE COATING OBTAINED BY ELECTRIC SPARK HARDENING

2020 ◽  
Vol 4 (141) ◽  
pp. 157-163
Author(s):  
IL’YA ROMANOV ◽  
◽  
ROMAN ZADOROZHNIY
Keyword(s):  
Wear Resistance ◽  
Reference Sample ◽  
Optical Microscope ◽  
Research Purpose ◽  
Tribotechnical Properties ◽  
Uncoated Surface ◽  
Before And After ◽  
Materials Used ◽  
Friction Track

When applying coatings using various methods on the surfaces of moving parts that work in joints, it is important to make sure that the coatings are strong and wear-resistant in order to return them to their original resource. All existing hardening technologies and materials used to perform coatings have their own characteristics, therefore, the quality of the resulting coatings can be judged only after specific tests. (Research purpose) The research purpose is in evaluating the properties of the coating obtained by the method of electric spark hardening, and its ability to resist friction and mechanical wear. (Materials and methods) Authors conducted tests on the basis of the "Nano-Center" center for collective use. A coating was applied on the BIG-4M unit with a VK-8 hard alloy electrode, tribological properties were evaluated on a CSM Instruments TRB-S-DE-0000 tribometer, the width of the friction track was measured after the test using an inverted OLYMPUS gx51 optical microscope, and samples were weighed before and after the test on a VLR-200 analytical balance. Conducted research in accordance with GOST 23.224-86 and RD 50-662-88 guidelines. (Results and discussion) The article presents performed tests on the run-in and wear resistance of the coating. The samples were worked on with a step-by-step increase in the load. During the tests, the friction force was drawed on the diagram. Authors compared the results with the reference sample, an uncoated surface. (Conclusions) The resulting coating has better run-in and wear resistance compared to the standard, and the increase in wear resistance in dry friction conditions is very significant.

scholarly journals Correlation between Defects and Technical Wear of Materials Used in Traditional Construction

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2482
Author(s):  
Jarosław Konior ◽  
Mariusz Rejment
Keyword(s):  
Residential Buildings ◽  
Descriptive Analysis ◽  
Technical Condition ◽  
Water Penetration ◽  
Major Drawback ◽  
Wear Process ◽  
Materials Used ◽  
Traditional Construction ◽  
The Relationship ◽  
Measurable Property

The degree of technical wear of old buildings, which are made of basic materials (cement, concrete, steel, timber, plaster, brick) using traditional technology, is expressed by the size and intensity of damage to their elements. The topic of the research concerns old residential buildings from the turn of the 19th and 20th centuries, which are located in the downtown district of Wroclaw, Poland. The descriptive analysis and the analysis of the definitions of defects that occur in the elements of residential buildings, which were performed as random analyzes, do not allow defects to be considered as measurable variables at a level of visual investigation. The major drawback of the method that is used by experts when assessing the technical condition of civil engineering buildings is that it does not numerically express the magnitude (strength) of the defects. Therefore, an attempt was made to numerically express the relationship (if such a relationship exists) between the occurred defects of buildings and the extent of their technical wear process. When calculating the strength of this relationship, the method of determining the point biserial correlation coefficient for the measurable property and the dichotomous property was used. It was found that the direction of the relation is right-hand for all the tested building elements, but the strength of the correlation between the detected defects and technical wear shows a considerable span and depends on the conditions of the apartment house’s maintenance. As a rule, damage caused by water penetration and moisture penetration always shows correlations of at least moderate strength.

scholarly journals Study on the Dissolution and Precipitation Behavior of Self-Designed (NbTi)C Nanoparticles Addition in 1045 Steel

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 184
Author(s):  
Hongwei Zhu ◽  
Haonan Li ◽  
Furen Xiao ◽  
Zhixiang Gao
Keyword(s):  
Tensile Strength ◽  
Electron Microscope ◽  
Optical Microscope ◽  
Cast Steels ◽  
Uniform Dispersion ◽  
The Matrix ◽  
Thermo Calc Software ◽  
Particle Strengthening ◽  
1045 Steel ◽  
Addition Amount

Self-designed (NbTi)C nanoparticles were obtained by mechanical alloying, predispersed in Fe powder, and then added to 1045 steel to obtain modified cast steels. The microstructure of cast steels was investigated by an optical microscope, scanning electron microscope, X-ray diffraction, and a transmission electron microscope. The results showed that (NbTi)C particles can be added to steels and occur in the following forms: original ellipsoidal morphology nanoparticles with uniform dispersion in the matrix, cuboidal nanoparticles in the grain, and microparticles in the grain boundary. Calculations by Thermo-Calc software and solubility formula show that cuboidal (NbTi)C nanoparticles were precipitated in the grain, while the (NbTi)C microparticles were formed by eutectic transformation. The results of the tensile strength of steels show that the strength of modified steels increased and then declined with the increase in the addition amount. When the addition amount was 0.16 wt.%, the modified steel obtained the maximum tensile strength of 759.0 MPa, which is an increase of 52% compared with to that with no addition. The hardness of the modified steel increased with the addition of (NbTi)C nanoparticles. The performance increase was mainly related to grain refinement and the particle strengthening of (NbTi)C nanoparticles, and the performance degradation was related to the increase in eutectic (NbTi)C.

scholarly journals The Influence of Oxidative Stress on Serum Albumin Structure as a Carrier of Selected Diazaphenothiazine with Potential Anticancer Activity

2021 ◽  
Vol 14 (3) ◽  
pp. 285
Author(s):  
Małgorzata Maciążek-Jurczyk ◽  
Beata Morak-Młodawska ◽  
Małgorzata Jeleń ◽  
Wiktoria Kopeć ◽  
Agnieszka Szkudlarek ◽  
...  
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Anticancer Activity ◽  
Drug Distribution ◽  
Cd Spectroscopy ◽  
Drug Binding ◽  
Protein Activity ◽  
Chloramine T ◽  
The Stability

Albumin is one of the most important proteins in human blood. Among its multiple functions, drug binding is crucial in terms of drug distribution in human body. This protein undergoes many modifications that are certain to influence protein activity and affect its structure. One such reaction is albumin oxidation. Chloramine T is a strong oxidant. Solutions of human serum albumin, both non-modified and modified by chloramine T, were examined with the use of fluorescence, absorption and circular dichroism (CD) spectroscopy. 10H-3,6-diazaphenothiazine (DAPT) has anticancer activity and it has been studied for the first time in terms of binding with human serum albumin—its potential as a transporting protein. Using fluorescence spectroscopy, in the presence of dansylated amino acids, dansyl-l-glutamine (dGlu), dansyl-l-proline (dPro), DAPT binding with two main albumin sites—in subdomain IIA and IIIA—has been evaluated. Based on the conducted data, in order to measure the stability of DAPT complexes with human (HSA) and oxidized (oHSA) serum albumin, association constant (Ka) for ligand-HSA and ligand-oHSA complexes were calculated. It has been presumed that oxidation is not an important issue in terms of 10H-3,6-diazaphenothiazine binding to albumin. It means that the distribution of this substance is similar regardless of changes in albumin structure caused by oxidation, natural occurring in the organism.

scholarly journals Dual role of CO in the stability of subnano Pt clusters at the Fe3O4(001) surface

2016 ◽  
Vol 113 (32) ◽  
pp. 8921-8926 ◽  
Author(s):  
Roland Bliem ◽  
Jessi E. S. van der Hoeven ◽  
Jan Hulva ◽  
Jiri Pavelec ◽  
Oscar Gamba ◽  
...  
Keyword(s):  
Density Functional ◽  
Elevated Temperatures ◽  
Time Lapse ◽  
Dual Role ◽  
Oxidation Catalyst ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Active Metal ◽  
Catalytically Active ◽  
The Stability

Interactions between catalytically active metal particles and reactant gases depend strongly on the particle size, particularly in the subnanometer regime where the addition of just one atom can induce substantial changes in stability, morphology, and reactivity. Here, time-lapse scanning tunneling microscopy (STM) and density functional theory (DFT)-based calculations are used to study how CO exposure affects the stability of Pt adatoms and subnano clusters at the Fe3O4(001) surface, a model CO oxidation catalyst. The results reveal that CO plays a dual role: first, it induces mobility among otherwise stable Pt adatoms through the formation of Pt carbonyls (Pt1–CO), leading to agglomeration into subnano clusters. Second, the presence of the CO stabilizes the smallest clusters against decay at room temperature, significantly modifying the growth kinetics. At elevated temperatures, CO desorption results in a partial redispersion and recovery of the Pt adatom phase.

scholarly journals Analisis Kepuasan Pelanggan dalam Membeli Buah-buahan Segar di Moena Fresh Bali

2018 ◽  
pp. 81
Author(s):  
PUTU OKA WARDIKA ◽  
RATNA KOMALA DEWI ◽  
NI WAYAN PUTU ARTINI
Keyword(s):  
Data Analysis ◽  
Data Collection ◽  
Customer Satisfaction ◽  
Qualitative Data ◽  
Descriptive Analysis ◽  
Secondary Data ◽  
Satisfaction Index ◽  
The Matrix ◽  
Competitive Prices ◽  
Data Analysis Methods

Analysis Customer Satisfaction in Buying Fresh Fruits in Moena Fresh Bali Increased consumption of fruits in the country have an impact on the growth of fruitsales in Indonesia. This increase causes the appearance of stiff competition in thebusiness of fruits. Moena Fresh Bali as one of the companies that sell fresh fruitsmust innovate or improve the shortage so that the consumers do not turn to otherproducts. Consumer behavior may help explain how consumers obtain satisfaction.The purpose of this research is to determine satisfaction of Moena Fresh Baliconsumers and to find out actions to increase customer satisfaction of Moena Fresh.The location of the research was conducted at four Moena Fresh outlets as it wasconsidered to represent consumers in every sub-district in Denpasar City. Thenumber of respondents was as many as 50 respondents and the sampling wasconducted by using accidental sampling. Types of data collected include quantitativeand qualitative data which were sourced from primary and secondary data. Methodsof data collection were by using interview techniques, observation, anddocumentation. Data analysis methods used were descriptive analysis, ImportancePerformance Analysis and Customer Satisfaction Index. Based on the results ofresearch, the calculation of CSI to the attributes of Moena Fresh Bali was 77.6% i.e.it meets the criteria of satisfaction. Based on the Matrix of Importance Performance,product attributes are classified into four quadrants and actions to improve customersatisfaction are through the improvement of attributes that become the main priority,namely the attributes of advertising / promotion, price, and discounts. The studysuggests that Moena Fresh Bali should perform printed and electronic publicationsand set competitive prices to maintain its customers.

scholarly journals Development and Application of a Novel Pluri-Residue Method to Determine Polar Pesticides in Fruits and Vegetables through Liquid Chromatography High Resolution Mass Spectrometry

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 553
Author(s):  
Lorena Manzano-Sánchez ◽  
José Antonio Martínez-Martínez ◽  
Irene Domínguez ◽  
José Luis Martínez Vidal ◽  
Antonia Garrido Frenich ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
High Resolution ◽  
High Performance ◽  
Fruits And Vegetables ◽  
High Resolution Mass Spectrometry ◽  
Stationary Phases ◽  
Mean Values ◽  
Polar Pesticides ◽  
Relative Standard ◽  
The Matrix

Nowadays, highly polar pesticides are not included in multiresidue methods due to their physico-chemical characteristics and therefore, specific analytical methodologies are required for their analysis. Laboratories are still looking for a pluri-residue method that encompasses the largest number of polar pesticides. The aim of this work was the simultaneous determination of ethephon, 2-hydroxyethylphosphonic acid (HEPA), fosetyl aluminum, glyphosate, aminomethylphosphonic acid (AMPA), N-acetyl-glyphosate and N-acetyl-AMPA in tomatoes, oranges, aubergines and grapes. For that purpose, an ultra high performance liquid chromatography (UHPLC) coupled to a high resolution single mass spectrometer Orbitrap-MS were used. Different stationary phases were evaluated for chromatographic separation, and among them, the stationary phase Torus DEA provided the best separation of the selected compounds. The QuPPe method was used for the extraction of the analytes, but slight modifications were needed depending on the matrix. The developed method was validated, observing matrix effect in all matrices. Intra- and inter-day precision were estimated, and relative standard deviation were lower than 19%. Recoveries were satisfactory, and mean values ranged from 70% to 110%. Limits of quantification were between 25 and 100 µg kg−1. Finally, the analytical method was applied to different fruits and vegetables (oranges, tomatoes, aubergines and grapes).

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