scholarly journals Exploration of Processing Parameters of Vacuum Assisted Micelle Confinement Synthesis of Spherical CL-20 Microparticles

MRS Advances ◽  
2018 ◽  
Vol 3 (11) ◽  
pp. 553-561
Author(s):  
Kaifu Bian ◽  
Leanne Alarid ◽  
David Rosenberg ◽  
Hongyou Fan
Keyword(s):  
Energetic Material ◽  
Particle Growth ◽  
Element Model ◽  
Processing Parameters ◽  
Critical Parameters ◽  
Operation Conditions ◽  
Explosive Devices ◽  
Further Development

ABSTRACTWe recently developed a vacuum assisted micelle confinement synthesis for spherical microparticles of CL-20 with outstanding monodispersity. These microparticles are promising energetic material for explosive devices with enhanced and predictable performances. In this work, to facilitate further development and application of this synthesis, the particle growth process was monitored by in-situ dynamic light scattering measurements. The result was interpreted by a finite element model to obtain critical parameters. These parameters were then used to predict the behavior and product quality of batch synthesis under various operation conditions.

scholarly journals Hygienic quality of public natural swimming pools (NSP)

2018 ◽  
Vol 19 (2) ◽  
pp. 365-370
Author(s):  
Stefan Bruns ◽  
Christina Peppler
Keyword(s):  
Water Treatment ◽  
Elimination Rate ◽  
Ex Situ ◽  
Swimming Pools ◽  
Private And Public ◽  
External Water ◽  
Log Steps ◽  
Further Development

Abstract Natural swimming pools (NSP) have become more popular in the past 20 years, both for private and public use, but their hygienic status remains a matter of discussion. Elimination rates in NSP are well defined for Escherichia coli, enterococci and Pseudomonas but a lack of knowledge exists regarding elimination rates in NSP concerning the parasitic protozoans Giardia and Cryptosporidium. First studies indicate that in-situ zooplankton filtration proved to reduce these protozoans efficiently: the in-situ elimination of Cryptosporidium is dependent on the population of zooplankton. In the 50% percentile the elimination rate is four times faster than in the chlorinated pool. The ex-situ elimination of Cryptosporidium in an NSP is approximately 10% faster than in a chlorinated pool. In ex-situ treatment of NSP the elimination rate reached 2 log-steps versus 1 log-step in chlorinated pools. For the further development of NSP for the best possible hygiene and health status some elementary questions, stated in this paper, will have to be solved in the next years or decades. This work describes the in-situ (water treatment inside the pool) and ex-situ water treatment (water treatment via external water treatment plants) of NSP, and the influence of zooplankton in existing NSP on the elimination rate of Cryptosporidium and Giardia.

scholarly journals Improved in situ performance testing of line-concentrating solar collectors: Comprehensive uncertainty analysis for the selection of measurement instrumentation

2016 ◽  
Author(s):  
Annie Zirkel-Hofer ◽  
Stephen Perry ◽  
Sven Fahr ◽  
Korbinian Kramer ◽  
Anna Heimsath ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Performance Testing ◽  
Evaluation Procedure ◽  
Test Results ◽  
Solar Collectors ◽  
Further Development ◽  
Testing And Evaluation ◽  
Selection Of

Accurate and complete performance evaluation is playing a major role in the further development of concentrating solar collectors. To ensure dependable test results, an appropriate testing and evaluation procedure is required. Moreover, the selection and installation of suitable  measurement instrumentation are essential for obtaining reliable data for the performance evaluation. The quality of the measurement instrumentation greatly influences the representativeness of the test results. Details on the measurement instrumentation recommended for the testing of low-temperature solar collectors have already been provided in the testing standard EN ISO 9806:2013.

Development of Welding Technology for Tracked Vehicle Track Based on Computer-simulated Stress-Strain State

2018 ◽  
pp. 1-9
Author(s):  
D. Yu. Titiov ◽  
S. A. Korolev
Keyword(s):  
Computer Simulation ◽  
Thermal Strain ◽  
Element Model ◽  
Tracked Vehicle ◽  
Optimal Method ◽  
Material Resources ◽  
Operation Conditions ◽  
Simulation Techniques ◽  
Residual Displacements

The article dwells on the applications of computer simulation techniques to solve specific tasks in manufacturing. The problem under consideration is relevant because these broadly used methods allow us to save a significant amount of time and material resources, which is an important factor in current manufacturing operation conditions.Conducts computer analysis of thermal strain processes occurred when welding a track of the tracked vehicle chain component. Performs a finite-element model of the product, specifies the material and environment properties, the fastening conditions, and the welding modes. Considers three options for laying welds. Based on simulation results, residual displacements, arising in the crest during welding, have been obtained. The most optimal method for laying welds is selected where no further product post-treatment is required.The study shows that computer simulation is an efficient tool to solve the tasks, when their analytical calculating is impossible or in case it is unreasonable to conduct full-scale experiments because of high costs. Varying of different parameters allows us to estimate a quality of developed technology without multiple experiments.

scholarly journals Finite Element Analysis of Cornea and Lid Wiper During Blink, With and Without Contact Lens

2020 ◽  
Author(s):  
Vivek R ◽  
Meenatchi S ◽  
Rinu Thomas ◽  
Ramesh Ve ◽  
Raghuvir Pai ◽  
...  
Keyword(s):  
Finite Element ◽  
Contact Lens ◽  
Element Model ◽  
Biomechanical Properties ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Biomechanical Changes ◽  
Von Mises

Abstract Contact Lens-related Discomfort (CLD) is one of the major problems in about 50% of contact lens users. It is a symptom of a variety of conditions such as Lid Wiper Epitheliopathy (LWE), Superior Epithelial Arcuate Lesion (SEAL), Limbal Stem Cell Deficiency (LSCD), Superior Limbic Keratoconjunctivitis (SLK) and dry eye disease; which affect the quality of life. Hence, it is essential to investigate the underlying cause of CLD. During a blink, the under surface of the eyelid tends to interact with the cornea and the conjunctiva. The presence of a contact lens can add to the biomechanical changes on these surfaces. To estimate these changes with and without a contact lens, a Finite Element Model (FEM) of the eyelid wiper, eyeball and contact lens was developed using COMSOL Multiphysics®. Biomechanical properties such as von Mises stress and displacement were calculated. Our study concluded that large stress formed in the lid wiper could be the reason for the occurrence of LWE and SLK without contact lens in the eye. When the contact lens was in situ, large stress was found in the superior 1.3mm of the cornea which could be responsible for the development of SEAL and superior LSCD.

Cognitive Health Counseling 40+

2013 ◽  
Vol 21 (1) ◽  
pp. 24-33 ◽  
Author(s):  
Anne Eschen ◽  
Franzisca Zehnder ◽  
Mike Martin
Keyword(s):  
Outcome Variable ◽  
Pilot Phase ◽  
Subjective Memory ◽  
Cognitive Health ◽  
Health Counseling ◽  
Agents Of Change ◽  
Main Outcome Variable ◽  
Further Development

This article introduces Cognitive Health Counseling 40+ (CH.CO40+), an individualized intervention that is conceptually based on the orchestration model of quality-of-life management ( Martin & Kliegel, 2010 ) and aims at improving satisfaction with cognitive health in adults aged 40 years and older. We describe the theoretically deduced characteristics of CH.CO40+, its target group, its multifactorial nature, its individualization, the application of subjective and objective measures, the role of participants as agents of change, and the rationale for choosing participants’ satisfaction with their cognitive health as main outcome variable. A pilot phase with 15 middle-aged and six older adults suggests that CH.CO40+ attracts, and may be particularly suitable for, subjective memory complainers. Implications of the pilot data for the further development of the intervention are discussed.

Qualitative assessment of equipment failure cause finding and removal

2018 ◽  
pp. 116-126
Author(s):  
E. A. Vakulin ◽  
A. I. Zayats ◽  
V. A. Beklemeshev ◽  
V. A. Ivashkevich ◽  
V. A. Khazhiev ◽  
...  
Keyword(s):  
Production Condition ◽  
Real Life ◽  
Open Pit Mine ◽  
Qualitative Assessment ◽  
Open Pit ◽  
Quality Level ◽  
Equipment Failure ◽  
Operation Conditions ◽  
Failure Investigation

Investigation of failures is one of the critical activities of mining and haulage equipment operability assurance in mining. Maintaining failure investigation at the required quality level, it is possible to identify provisions, rules and procedures that should be revised or changed, operation conditions that should be improved, additional personnel training, if required, etc. Investigation of failures in mines is under responsibility of machine men and electricians of maintenance and operation services. In reality, factory management and setup for production condition weak concernment of these workers in quality investigation aimed at finding of sources of equipment failures. This article describes real-life results achieved in development and use of maintenance service operation, technology and management monitoring. The requirements are substantiated for quality improvement in failure cause finding and removal in mining and haulage equipment at Chernogorsky open pit mine, SUEK-Khakassia. Causes of the present quality of failure investigation by machine men of Chernogorsky Repair and Engineering Works and Chernogorsky open pit mine are revealed. The proposed recommended practices will improve quality of mining and haulage equipment failure investigation.

A geometallurgical characterization study of the Crystalkop Reef at the Great Noligwa Mine, Klerksdorp Goldfield, South Africa

2017 ◽  
Vol 120 (3) ◽  
pp. 303-322
Author(s):  
D. Pienaar ◽  
B.M. Guy ◽  
C. Pienaar ◽  
K.S. Viljoen
Keyword(s):  
South Africa ◽  
Treatment Plant ◽  
Processing Parameters ◽  
Processing Plant ◽  
Small Contribution ◽  
Gold Cyanide ◽  
Three Samples ◽  
Characterization Study ◽  
Different Sources

Abstract Mineralogical and textural variability of ores from different sources commonly leads to processing inefficiencies, particularly when a processing plant is designed to treat ore from a single source (i.e. ore of a relatively uniform composition). The bulk of the Witwatersrand ore in the Klerksdorp goldfield, processed at the AngloGold Ashanti Great Noligwa treatment plant, is derived from the Vaal Reef (>90%), with a comparatively small contribution obtained from the Crystalkop Reef (or C-Reef). Despite the uneven contribution, it is of critical importance to ensure that the processing parameters are optimized for the treatment of both the Vaal and C-Reefs. This paper serves to document the results of a geometallurgical study of the C-Reef at the Great Noligwa gold mine in the Klerksdorp goldfield of South Africa, with the primary aim of assessing the suitability of the processing parameters that are in use at the Great Noligwa plant. The paper also draws comparisons between the C-Reef and the Vaal Reef A-facies (Vaal Reef) and attempts to explain minor differences in the recovery of gold and uranium from these two sources. Three samples of the C-Reef were collected in-situ from the underground operations at Great Noligwa mine for mineralogical analyses and metallurgical tests. Laboratory-scale leach tests for gold (cyanide) and uranium (sulphuric acid) were carried out using dissolution conditions similar to that in use at the Great Noligwa plant, followed by further diagnostic leaching in the case of gold. The gold in the ore was found to be readily leachable with recoveries ranging from 95% to 97% (as opposed to 89% to 93% for the Vaal Reef). Additional recoveries were achieved in the presence of excess cyanide (96% to 98%). The recovery of uranium varied between 72% and 76% (as opposed to 30% to 64% for the Vaal Reef), which is substantially higher than predicted, given the amount of brannerite in the ore, which is generally regarded as refractory. Thus, the higher uranium recoveries from the C-Reef imply that a proportion of the uranium was recovered by the partial dissolution of brannerite. As the Vaal Reef contain high amounts of chlorite (3% to 8%), which is an important acid consumer, it is considered likely that this could have reduced the effectiveness of the H2SO4 leach in the case of the ore of the Vaal Reef. Since the gold and uranium recoveries from the C-Reef were higher than the recoveries from the Vaal Reef, the results demonstrate that the processing parameters used for treatment of the Vaal Reef are equally suited to the treatment of the C-Reef. Moreover, small processing modifications, such as increased milling and leach retention times, may well increase the recovery of gold (particularly when e.g. coarse gold, or unexposed gold, is present).

Pengaruh Jenis Co-Solvent terhadap Rendemen dan Mutu Biodiesel secara Transesterifikasi In Situ Menggunakan Radiasi Gelombang Mikro

2016 ◽  
Vol 10 (2) ◽  
pp. 119-126
Author(s):  
Mahlinda Mahlinda ◽  
Fitriana Djafar
Keyword(s):  
Catalyst Concentration ◽  
Maximum Yield ◽  
Acid Value ◽  
Experimental Result ◽  
In Situ Transesterification ◽  
Yield And Quality ◽  
Solvent Type ◽  
Biodiesel Quality

The main purpose of this research was to observer effect co-solvent type (n-Hexane, chloroform and without co-solvent)  toward yield and quality of biodiesel via in situ transesterification process using microwave irradiation. The process was studied at microwave power 450 watt, reaction time 4 minutes, methanol to seed ratio 25:1 and catalyst concentration 5%. The physicochemical parameters of the biodiesel produced such as viscosity, density and acid value were analysed and compared with the SNI 7182-2012 standard. The experimental result showed the maximum yield biodiesel 78,32% obtained by using co-solvent chloroform.Test result of physicochemical properties (viscosity, density and acid value) of biodiesel products using co solvent n-Hexane, chloroform and without co solvent showed that these products conform to the SNI 7182-2012 standars. The type of co-solvent only affectedon biodiesel yield dan not affected on biodiesel quality (viscosity, density and acid value).  ABSTRAKTujuan penelitian ini adalah untuk mempelajari pengaruh jenis co-solvent (n-Hexane, chloroform dan tanpa co-solvent) terhadap rendemen dan mutu biodiesel secara trasesterifikasi in situ menggunakan radiasi gelombang mikro. Proses dilakukan pada daya gelombang mikro 450 watt, waktu reaksi 4 menit, perbandingan berat metanol terhadap bahan baku 25:1 dan jumlah katalis 5%. Parameter fisiko kimia dari produk biodiesel seperti viskositas, densitas dan angka asam di analisa dan dibandingkan dengan standar SNI 7182-2012 tentang biodiesel. Hasil penelitian menunjukkan rendemen maksimum biodiesel sebesar 78,32% diperoleh dengan menggunakan co-solvent chloroform. Hasil pengujian  karakteristik fisiko kimia (viskositas, densitas dan angka asam) dari produk biodiesel menggunakan co-solvent n-Hexane, chloroform dan tanpa co-solvent menunjukkan bahwa semua parameter ini masih memenuhi standar SNI 1782-2012 tentang biodiesel. Jenis co-solvent hanya berpengaruh pada rendemen biodiesel dan tidak berpengaruh terhadap mutu biodiesel (viskositas, densitas dan bilangan asam).Kata kunci: co-solvent, in situ transesterifikasi, microwave, rendemen, mutu   

Estudio del proceso de lavado de contenedores para eliminar tiempos y movimientos innecesarios, caso: Wash Containers S.A de C.V.

2020 ◽  
pp. 25-36
Author(s):  
Juan Alfredo Lino-Gamiño ◽  
Carlos Méndez-González ◽  
Eduardo José Salazar-Araujo ◽  
Pablo Adrián Magaña-Sánchez
Keyword(s):  
Business Process ◽  
Value Chain ◽  
Process Management ◽  
Core Business ◽  
The Core ◽  
Washing Process ◽  
Overall Performance ◽  
The Times

In the value chain it is important to keep in mind the core business of the company, since it depends largely on the competitiveness of the company and its overall performance, bearing in mind that all business indicators depend on it. In this work we will study the washing process within the company WASH CONTAINERS SA DE CV, to improve the washing processes and in this way reduce times and movements in the process leading the company to reduce costs considerably within the operations company daily, having a more competitive operation and with greater profit margin in its business process. Goals: It Improve the logistics of the movement of containers for washing and with it the core business of the company. Methodology: The action research will be applied applying Business Process Management for the improvement of processes in situ, it will be developed in a certain period of time and with that it will establish an improvement projection. Contribution: The improvement of the times for the disposal of the containers and their subsequent use, allows a better competitiveness and with it the income of the company, on the other hand, the transport companies improve in performance in quantity, quality of disposition and with it their income.

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