Propiedades físico-mecánicas de tres especies de nopal de alto consumo en México

Nopal is one of the most consumed foods in Mexico (consumed both by humans and animals, mainly ruminants), with an increased demand in the last ten years. The nopal (Opuntia spp.) develops favorably in conditions of low precipitation, in thin, rocky soils which are typical of arid zones, where other crops only grow at a certain time of the year. The physical-mechanical properties of the product to be processed are fundamental in the design and construction of agricultural machinery, since previous knowledge and evaluation of the material that is going to be processed enables a correct selection of the work elements or mechanisms that will intervene in the machine. In the case of nopal processing, the presence of areolas and thorns directly affects some mechanical properties of the product, as presented in this paper.

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Mechanical properties of dental restorative materials: relative contribution of laboratory tests

Journal of Applied Oral Science ◽

10.1590/s1678-77572003000300002 ◽

2003 ◽

Vol 11 (3) ◽

pp. 162-167 ◽

Cited By ~ 69

Author(s):

Linda Wang ◽

Paulo Henrique Perlatti D'Alpino ◽

Lawrence Gonzaga Lopes ◽

José Carlos Pereira

Keyword(s):

Mechanical Properties ◽

Laboratory Tests ◽

Clinical Performance ◽

Dental Materials ◽

Correct Selection ◽

Relative Contribution ◽

Dental Restorative Materials ◽

Restorative Materials ◽

Dental Restorative ◽

Selection Of

A wide variety of dental products that are launched on the market becomes the correct selection of these materials a difficult task. Although the mechanical properties do not necessarily represent their actual clinical performance, they are used to guide the effects of changes in their composition or processing on these properties. Also, these tests might help somehow the clinician to choose once comparisons between former formulations and new ones, as well as, with the leading brand, are highlighted by manufactures. This paper presents a review of the most important laboratory tests. In this manner, the knowledge of these tests will provide a critical opinion related to the properties of different dental materials.

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Mechanical Properties and Mineralogical Composition of Potash Ore as a Factor in Selecting the Processing Method

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1022.17 ◽

2021 ◽

Vol 1022 ◽

pp. 17-26

Author(s):

Yana V. Kuskova ◽

Nikita A. Lipnitsky

Keyword(s):

Mechanical Properties ◽

Mining Industry ◽

Mineralogical Composition ◽

Core Material ◽

Correct Selection ◽

Dry Cleaning ◽

Size And Shape ◽

Natural Size ◽

Selection Of ◽

Intergranular Space

The correct selection of technology for processing potash ore depends on its mineralogical composition, the natural size and shape of grains, as well as on the amount and size of halite grains located in the intergranular space of sylvinites. The study of seams and mineralogical and petrographic studies of potash ore were carried out in order to determine the natural size of sylvinite grains, their shape, and the content of halite in the intergranular space.Moreover, the influence of these parameters on the beneficiation ability of the ore using dry cleaning process was determined. In addition, the data on laboratory studies using electric separation is provided in the paper. The results of the provided studies can be used by specialists of the mining industry when considering the influence of the mineral composition, size and shape of grains of potash ore in order to select the separation method at the early stages of development of potash deposits. The study of core material and mechanical properties, mineralogical and petrographic studies together with studies on beneficiation ability of ore presented in the article can be used, for example, in the preparation of a feasibility report.

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The Long Road to Sustainability

10.1093/oso/9780198819516.001.0001 ◽

2018 ◽

Cited By ~ 1

Author(s):

Alexander Gillespie

Keyword(s):

Sustainable Development ◽

Environmental Problem ◽

Social Sustainability ◽

Good News ◽

Correct Selection ◽

The Third ◽

Positive Indicators ◽

Laws And Policies ◽

Developed World ◽

Selection Of

This book examines the idea of sustainable development, made up of economic, social, and environmental parts over the period of human history. This work suggests humanity has been unsustainable in all three areas for most of its history, although in the last few hundred years the scale of unsustainability has increased, while, simultaneously, answers have started to emerge. This conclusion can be seen in two parts, namely the economic and social sides of sustainable development and then the environmental ones. This work suggests that, with the correct selection of tools, solid and positive foundations for the economic and social sides of sustainable development is possible as the world globalizes. This is not, however, a foregone conclusion. Despite a number of recent positive indicators in this area, there are still very large unanswered questions with existing mechanisms and other gaps in the international architecture which, if not fixed, could quickly make problems of economic and social sustainability worse, not better. With the third leg of sustainable development, that for the environment, the optimism is not as strong. The good news is that science, laws, and policies have evolved and expanded to the level that, in theory, there is no environmental problem which cannot be solved. In many areas, especially in the developed world, success is already easy to measure. Where it is not easy to measure, and pessimism creeps in, is in the developing world, which is now inheriting a scale and mixture of environmental difficulties which are simply unprecedented.

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Elaboration and Characterization of the Properties of Refractory Cr Base Alloys

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.72.46 ◽

2010 ◽

Vol 72 ◽

pp. 46-52 ◽

Cited By ~ 1

Author(s):

Laurent Royer ◽

Stéphane Mathieu ◽

Christophe Liebaut ◽

Pierre Steinmetz

Keyword(s):

Mechanical Properties ◽

Melting Point ◽

Molten Glass ◽

Energy Production ◽

Creep Properties ◽

Refractory Alloys ◽

Industrial Use ◽

Kinetics Of ◽

Selection Of

For energy production and also for the glass industry, finding new refractory alloys which could permit to increase the process temperatures to 1200°C or more is a permanent challenge. Chromium base alloys can be good candidates, considering the melting point of Cr itself, and also its low corrosion rate in molten glass. Two families of alloys have been studied for this purpose, Cr-Mo-W and Cr-Ta-X alloys (X= Mo, Si..). A finer selection of compositions has been done, to optimize their chemical and mechanical properties. Kinetics of HT oxidation by air, of corrosion by molten glass and also creep properties of several alloys have been measured up to 1250°C. The results obtained with the best alloys (Cr-Ta base) give positive indications as regards the possibility of their industrial use.

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Advances in Fabricating the Electrospun Biopolymer-Based Biomaterials

Journal of Functional Biomaterials ◽

10.3390/jfb12020026 ◽

2021 ◽

Vol 12 (2) ◽

pp. 26

Author(s):

Sebastian Wilk ◽

Aleksandra Benko

Keyword(s):

Mechanical Properties ◽

Whey Protein ◽

Antimicrobial Properties ◽

Protein Isolate ◽

Review Article ◽

Animal Tissues ◽

Green Material ◽

Good Potential ◽

Fibrous Morphology ◽

Selection Of

Biopolymers formed into a fibrous morphology through electrospinning are of increasing interest in the field of biomedicine due to their intrinsic biocompatibility and biodegradability and their ability to be biomimetic to various fibrous structures present in animal tissues. However, their mechanical properties are often unsatisfactory and their processing may be troublesome. Thus, extensive research interest is focused on improving these qualities. This review article presents the selection of the recent advances in techniques aimed to improve the electrospinnability of various biopolymers (polysaccharides, polynucleotides, peptides, and phospholipids). The electrospinning of single materials, and the variety of co-polymers, with and without additives, is covered. Additionally, various crosslinking strategies are presented. Examples of cytocompatibility, biocompatibility, and antimicrobial properties are analyzed. Special attention is given to whey protein isolate as an example of a novel, promising, green material with good potential in the field of biomedicine. This review ends with a brief summary and outlook for the biomedical applicability of electrospinnable biopolymers.

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Simulation Verification of the Contact Parameter Influence on the Forces’ Course of Cereal Grain Impact against a Stiff Surface

Applied Sciences ◽

10.3390/app11020466 ◽

2021 ◽

Vol 11 (2) ◽

pp. 466

Author(s):

Włodzimierz Kęska ◽

Jacek Marcinkiewicz ◽

Łukasz Gierz ◽

Żaneta Staszak ◽

Jarosław Selech ◽

...

Keyword(s):

Dynamic Properties ◽

Decisive Role ◽

Force Sensor ◽

Contact Forces ◽

Correct Selection ◽

Contact Parameter ◽

Cereal Grain ◽

Wide Range ◽

The Impact ◽

Selection Of

The continuous development of computer technology has made it applicable in many scientific fields, including research into a wide range of processes in agricultural machines. It allows the simulation of very complex physical phenomena, including grain motion. A recently discovered discrete element method (DEM) is used for this purpose. It involves direct integration of equations of grain system motion under the action of various forces, the most important of which are contact forces. The method’s accuracy depends mainly on precisely developed mathematical models of contacts. The creation of such models requires empirical validation, an experiment that investigates the course of contact forces at the moment of the impact of the grains. To achieve this, specialised test stations equipped with force and speed sensors were developed. The correct selection of testing equipment and interpretation of results play a decisive role in this type of research. This paper focuses on the evaluation of the force sensor dynamic properties’ influence on the measurement accuracy of the course of the plant grain impact forces against a stiff surface. The issue was examined using the computer simulation method. A proprietary computer software with the main calculation module and data input procedures, which presents results in a graphic form, was used for calculations. From the simulation, graphs of the contact force and force signal from the sensor were obtained. This helped to clearly indicate the essence of the correct selection of parameters used in the tests of sensors, which should be characterised by high resonance frequency.

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Procedure for the Selection of Rubber Compound in Rubber-Metal Springs for Vibration Isolation

Polymers ◽

10.3390/polym12081737 ◽

2020 ◽

Vol 12 (8) ◽

pp. 1737

Author(s):

Milan Banić ◽

Dušan Stamenković ◽

Aleksandar Miltenović ◽

Dragan Jovanović ◽

Milan Tica

Keyword(s):

Numerical Simulation ◽

Constitutive Model ◽

Vibration Isolation ◽

Correct Selection ◽

Virtual Experiment ◽

Rubber Compound ◽

Key Factor ◽

Railway Engineering ◽

Selection Of

The selection of a rubber compound has a determining influence on the final characteristics of rubber-metal springs. Therefore, the correct selection of a rubber compound is a key factor for development of rubber-metal vibration isolation springs with required characteristics. The procedure for the selection of the rubber compound for vibration isolation of rubber-metal springs has been proposed, so that the rubber-metal elements have the necessary characteristics, especially in terms of deflection. The procedure is based on numerical simulation of spring deflection with Bergström-Boyce constitutive model in virtual experiment, with a goal to determine which parameters of the constitutive model will lead to spring required deflection. The procedure was verified by case study defined to select rubber compound for a rubber–metal spring used in railway engineering.

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Generalization with Precision: The Role of Negative Teaching Examples in the Instruction of Generalized Grocery Item Selection

Journal of the Association for Persons with Severe Handicaps ◽

10.1177/154079698601100411 ◽

1986 ◽

Vol 11 (4) ◽

pp. 300-308 ◽

Cited By ~ 23

Author(s):

Robert H. Horner ◽

Richard W. Albin ◽

Ginevera Ralph

Keyword(s):

Young Adults ◽

Grocery Store ◽

Item Selection ◽

Multiple Baseline ◽

Correct Selection ◽

Correct Rejection ◽

Baseline Design ◽

Dependent Variables ◽

Selection Of

For generalization to be functional, it must occur with a precision that results in acquired responses occurring under appropriate, nontrained conditions, and acquired responses not occurring under inappropriate, nontrained conditions. This study examines the effect of differing types of negative teaching examples on the precision with which generalized grocery item selection is learned. Within a split-multiple baseline design, six young adults identified as mildly, moderately, or severely mentally retarded were trained to select or to reject grocery items using picture cards as cues. The dependent variables were correct selection of 10 trained “positive” grocery items and the correct rejection of 20 nontrained “negative” grocery items in a nontrained grocery store. Participants were trained in a grocery store to select 10 positive grocery examples matching their picture cards and to reject either (a) a set of negative examples that were maximally different from the positive examples, or (b) a set of negative examples that were minimally different from the positive examples. Both training sets resulted in participants correctly selecting the 10 positive items in a nontrained store. Training with the “minimally different” negative examples was functionally related to improved rejection of nontrained negative items in the nontrained store. The implications of teaching with minimally different, negative examples are discussed.

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The impact of the health condition of oaks from the Krotoszyn Plateau on the mechanical properties of timber structures

Folia Forestalia Polonica ◽

10.1515/ffp-2015-0023 ◽

2015 ◽

Vol 57 (4) ◽

pp. 224-232

Author(s):

Jarosław Siwiński ◽

Katarzyna Kubiak ◽

Miłosz Tkaczyk ◽

Anna Mazur ◽

Ryszard Rekucki

Keyword(s):

Mechanical Properties ◽

Health Condition ◽

Health State ◽

Timber Structures ◽

Strength Parameters ◽

Modified Method ◽

Strength Tests ◽

Prior Selection ◽

The Impact ◽

Selection Of

Abstract The study was conducted to perform a comparative analysis of the mechanical properties of wood samples derived from oaks in the Krotoszyn Plateau, which depend on the health state of the trees. Strength parameters of oak wood were calculated for selected diseased and healthy trees (according to the Roloff classification). The study was conducted by a modified method described in the standard Polish Norm PN EN 408+ A1: 2012. For testing, prior selection of wood samples showed that more wood samples of diseased trees compared with those of healthy oaks did not fulfil the Polish standard requirements. According to the method used, the average results of strength tests of timber structures from healthy oaks exhibited higher strength parameters than those of the diseased trees.

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Influence of the Chemical Composition on Electrical Conductivity and Mechanical Properties of the Hypoeutectic Al-Si-Mg Alloys

Archives of Metallurgy and Materials ◽

10.1515/amm-2016-0065 ◽

2016 ◽

Vol 61 (1) ◽

pp. 353-360 ◽

Cited By ~ 3

Author(s):

B. Dybowski ◽

J. Szymszal ◽

Ł. Poloczek ◽

A. Kiełbus

Keyword(s):

Mechanical Properties ◽

Electrical Conductivity ◽

Chemical Composition ◽

Aluminium Alloys ◽

Mg Alloys ◽

High Electrical Conductivity ◽

Transportation Industry ◽

Proper Selection ◽

Ti Addition ◽

Selection Of

Due to low density and good mechanical properties, aluminium alloys are widely applied in transportation industry. Moreover, they are characterized by the specific physical properties, such as high electrical conductivity. This led to application of the hypoeutectic Al-Si-Mg alloys in the power generation industry. Proper selection of the alloys chemical composition is an important stage in achievement of the demanded properties. The following paper presents results of the research on the influence of alloys chemical composition on their properties. It has been revealed that Si and Ti addition decreases electrical conductivity of the Al-Si-Mg alloys, while Na addition increases it. The mechanical properties of the investigated alloys are decreased by both silicon and iron presence. Sodium addition increases ductility of the Al-Si-Mg alloys.

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