Preliminary evaluation of the influence of surfactant injection on the mechanical behaviour of a compacted till

1995 ◽  
Vol 32 (3) ◽  
pp. 539-544
Author(s):  
Alexandre R. Cabral ◽  
Guy Lefebvre ◽  
Pascal Collette
Keyword(s):  
Mechanical Properties ◽  
Applied Pressure ◽  
Soil Mass ◽  
Preliminary Evaluation ◽  
Test Results ◽  
One Dimensional ◽  
Surfactant Solutions ◽  
Significant Compression ◽  
Soil Behaviour ◽  
Selection Of

One-dimensional consolidation tests were performed with till samples compacted dry of optimum to 85% of the modified Proctor density. When the applied pressure reached 200 kPa, the samples were saturated (submerged) and then flushed with two types of surfactant solutions, under a hydraulic gradient varying from 35 to 40. Significant compression occurred during submergence and as a result of flushing with a 2% solution of an anionic surfactant. Only minor additional compression resulted from flushing with a 2% solution of a nonionic surfactant. While only preliminary conclusions could be drawn from the limited test results, this study highlighted the importance of considering, in the early stages of remediation procedure design (including the selection of the surfactant), the possible deleterious effects of surfactant injection on the mechanical properties of the soil mass, particularly when it is in a loose to moderately loose state. Key words : surfactants, adsorption, hydrocarbon remediation, compression, mechanical properties, soil behaviour.

Selection of Equations-of-State for Blast Attenuation

1971 ◽  
Vol 38 (1) ◽  
pp. 253-261 ◽  
Author(s):  
P. Lieberman
Keyword(s):  
Boundary Condition ◽  
Equations Of State ◽  
Rear Surface ◽  
Applied Pressure ◽  
Rigid Boundary ◽  
One Dimensional ◽  
Number Of Layers ◽  
State Boundary ◽  
Analytical Expressions ◽  
Selection Of

Blast shield materials are described by idealized equations-of-state in both one-dimensional loading and one-dimensional unloading. A square-wave applied pressure history is one boundary condition at the impingement surface of the material and, at the rear surface of the material(s), there is a stationary boundary condition. The objective is to select the equations-of-state that yield the greatest reduction in reflected stress at the rigid-boundary condition, for the smallest overall length, for application to a blast shield. One and two layers of material are considered. Idealizations of the equations-of-state, boundary conditions, length of each layer, and number of layers are arranged to yield simple analytical expressions for the relation of reflected stress to the overall length of the blast shield.

scholarly journals Weathering-induced deformation of crushed weak rocks and its countermeasure

2019 ◽  
Vol 92 ◽  
pp. 09003
Author(s):  
Andius D. Putra ◽  
Masaya Takahashi ◽  
Mamoru Kikumoto
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Compression Stress ◽  
Test Results ◽  
Compression Tests ◽  
Wetting And Drying ◽  
Weak Rocks ◽  
One Dimensional ◽  
Significant Compression ◽  
Hydraulic Process

Geotechnical issues such as differential settlements have been reported usually in embankments made of materials derived from weak rocks such as mudstones, siltstones, and shales. The primary cause of the issue is a gradual weakening due to weathering. Crushed weak rocks tend to turn into smaller particles under repeated wetting and drying processes. This phenomenon is a mechanical-hydraulic process known as “slaking”. The present paper discusses the deformation of crushed weak rocks due to slaking and its countermeasure. We performed a series of one-dimensional slaking tests on several weak rocks. We first performed one-dimensional compression tests on dried samples, and applied wetting and drying cycles to the samples while keeping the compression stress constant. The test results revealed that particle size distribution of the samples was broadened due to cyclic wetting and drying processes and that significant compression was exhibited. Moreover, we explored possible countermeasures for reducing the slaking-induced deformation and revealed that compacting the soil to a denser state is the most effective way in reducing the slaking-induced deformation of the crushed mudstone.

Some Observations on Rubber Testing

1934 ◽  
Vol 7 (1) ◽  
pp. 142-146
Author(s):  
J. R. Scott
Keyword(s):  
Mechanical Properties ◽  
Present Note ◽  
Test Methods ◽  
Present Writer ◽  
Published Data ◽  
Test Results ◽  
Insufficient Attention ◽  
Strontium Sulfate ◽  
The Subject ◽  
Selection Of

Abstract The subject of rubber testing and its standardization has received so much attention in recent years, that some apology might seem necessary for discussing it further. A few years ago the present writer had occasion to call attention to several respects in which existing test methods showed unnecessary lack of uniformity (Trans. Inst. Rubber Ind., 5, 139 (1929)), and it must be admitted that this lack of uniformity still persists to a great extent, with a corresponding loss in the value of published test results. It is the object of the present note to call attention more particularly to some unsatisfactory features in the selection of the “best” or “optimum” cure of a mix for purposes of comparison with other mixes. It is scarcely necessary to emphasize the fact that in comparing the properties of different mixings, as in examining the effects of fillers, accelerators, antioxidants, softeners, etc., all the mixings must be vulcanized to comparable states of cure. Nevertheless, an examination of published data shows that often insufficient attention is paid to ensuring strict comparability. For instance, it is not uncommon to find the effect of fillers examined by taking an accelerated base stock, adding the fillers to it, and vulcanizing all the resulting mixings for the same time, it being assumed that the fillers do not affect rate of cure. This assumption is not justifiable, even in the case of seemingly inert materials. An obvious case is that of gas black, which, though chemically inert, retards vulcanization in presence of organic accelerators. Moreover, such “inert” materials as barytes, blanc fixe, whiting, and strontium sulfate may markedly alter the rate of cure. Thus, in some experiments made by the writer, a base mix accelerated with dephenylguanidine (0.75% on the rubber) gave optimum mechanical properties after 90 minutes at 141° C., but mixings containing the fillers mentioned had optimum curing times ranging from 65 to 110 minutes. The writer has, indeed, come across a filler consisting of a very inert compound, which nevertheless completely puts out of action the most powerful organic accelerators. It is thus clearly unsafe to assume that any material will be inert as regards its effect on rate of vulcanization, whether in presence of an organic accelerator or not.

Implementasi Voip Server Berbasis IPV6 Dengan Raspberry PI

2019 ◽  
Vol 9 (01) ◽  
pp. 47-54
Author(s):  
Rabbai San Arif ◽  
Yuli Fitrisia ◽  
Agus Urip Ari Wibowo
Keyword(s):  
Internet Protocol ◽  
Wireless Transmission ◽  
Raspberry Pi ◽  
Test Results ◽  
Average Delay ◽  
Ipv6 Network ◽  
Ip Network ◽  
Selection Of ◽  
Better Than

Voice over Internet Protocol (VoIP) is a telecommunications technology that is able to pass the communication service in Internet Protocol networks so as to allow communicating between users in an IP network. However VoIP technology still has weakness in the Quality of Service (QoS). VOPI weaknesses is affected by the selection of the physical servers used. In this research, VoIP is configured on Linux operating system with Asterisk as VoIP application server and integrated on a Raspberry Pi by using wired and wireless network as the transmission medium. Because of depletion of IPv4 capacity that can be used on the network, it needs to be applied to VoIP system using the IPv6 network protocol with supports devices. The test results by using a wired transmission medium that has obtained are the average delay is 117.851 ms, jitter is 5.796 ms, packet loss is 0.38%, throughput is 962.861 kbps, 8.33% of CPU usage and 59.33% of memory usage. The analysis shows that the wired transmission media is better than the wireless transmission media and wireless-wired.

PENGEMBANGAN BAHAN AJAR IPA SMP PADA TEMA ENERGI DALAM TUBUH MENGGUNAKAN METODE 4STMD

EDUSAINS ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 166-175
Author(s):  
Gia Juniar Nur Wahidah ◽  
Sjaeful Anwar
Keyword(s):  
Concept Maps ◽  
The Body ◽  
Instructional Materials ◽  
Teaching Material ◽  
Test Results ◽  
Teaching Materials ◽  
Eligibility Criteria ◽  
Material Development ◽  
Selection Step ◽  
Selection Of

Abstract This research aims to produce science teaching materials in junior level with Energy in The Body as the theme using Four Steps Teaching Material Development  (4STMD). The material is presented in an integrated way so that students can  think holistically and contextually. The method used in this study is Research and Development. In this R&D methods is used 4STMD. There are four steps done on the development of teaching materials, the selection step, structuring step, characterization, and didactic reduction. Selection step includes the selection of indicators in accordance with the demands of the curriculum which is then developed with the selection of concepts and values that are integrated with the concept of science. Structuring step includes make macro structures, concept maps, and multiple representations. Characterization's step includes preparation instruments, then  trial to students to identify difficult concepts. The last, didactic reduction was done by neglect and the annotations in the form of sketches.The test results readability aspect instructional materials lead to the conclusion that by determining the main idea, the legibility of teaching materials reached 67%, with moderate readability criteria. Test results of feasibility aspects based on the results of questionnaires to the 11 teachers lead to the conclusion that the overall, level of eligibility teaching materials reached 91% with the eligibility criteria well. Keywords: teaching materials; energy; 4STMD Abstrak Penelitian ini bertujuan untuk menghasilkan bahan ajar IPA SMP pada tema Energi dalam Tubuh menggunakan metode Four Steps Teaching Material Development (4STMD). Materi disajikan secara terpadu sehingga memacu siswa untuk berpikir secara holistik dan kontekstual. Metode penelitian yang digunakan pada penelitian ini adalah metode penelitian dan pengembangan. Dalam penelitian dan pengembangan yang ini, digunakan metode Four Steps Teaching Material Development (4STMD). Terdapat empat tahap yang dilakukan pada pengembangan bahan ajar, yakni tahap seleksi, strukturisasi, karakterisasi, dan reduksi didaktik. Tahap seleksi meliputi pemilihan indikator yang sesuai dengan tuntutan kurikulum yang kemudian dikembangkan dengan pemilihan konsep dan nilai yang diintegrasikan dengan konsep IPA. Tahap strukturisasi meliputi pembuatan struktur makro, peta konsep, dan multipel representasi dari materi. Tahap karakterisasi meliputi penyusunan instrumen karakterisasi, kemudian uji coba kepada siswa untuk mengidentifikasi konsep sulit. Tahap terakhir, yaitu reduksi didaktik konsep terhadap konsep sulit. Reduksi didaktik yang dilakukan berupa pengabaian dan penggunaan penjelasan berupa sketsa. Hasil uji aspek keterbacaan bahan ajar menghasilkan kesimpulan bahwa berdasarkan penentuan ide pokok, keterbacaan bahan ajar mencapai 67%, dengan kriteria keterbacaan tinggi. Hasil uji aspek kelayakan berdasarkan hasil angket terhadap 11 orang guru menghasilkan kesimpulan bahwa secara keseluruhan tingkat kelayakan bahan ajar mencapai 91% dengan kriteria kelayakan baik sekali. Kata Kunci: bahan ajar; energi; 4STMD  Permalink/DOI: http://dx.doi.org/10.15408/es.v8i2.2039  

HUBUNGAN UMUR DAN PARITAS DENGAN PEMILIHAN ALAT KONTRASEPSI METODE OPERASI WANITA (MOW) DI POLIKLINIK KEBIDANAN RS BHAYANGKARA PALEMBANG TAHUN 2012

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
Y. Widyastuti Y. Widyastuti
Keyword(s):  
Family Planning ◽  
Medical Records ◽  
Test Results ◽  
Family Planning Services ◽  
Chi Square ◽  
Cross Sectional ◽  
Planning Methods ◽  
Chi Square Test ◽  
Family Planning Methods ◽  
Selection Of

  ABSTRACT [In advanced countries the number of permanent contraception option ( kontap ) approximately 10 % of all national family planning methods , while in Indonesia reached approximately 5.7 % . Based on data obtained from medical records Bhayangkara Hospital Palembang in 2010 the number of achievement when seen from the percentage of contraceptive use is only 9.10 % The purpose of this study is known age and parity relationship with the selection of contraceptive methods Surgery Women ( MOW ) in Palembang RS.Bhayangkara obstetrics clinic in 2012 . This study uses the analytic survey with cross sectional approach . The population in this study were women who become new acceptors were recorded in medical records at the hospital . Palembang Bhayangkara Hospitals January 1, 2012 to December 31 in 2012 . The sample in this study is part of a whole number of new acceptors ( either using contraception methods MOW and other family planning methods ) were registered in the hospital . Palembang Police Hospitals of January 1, 2012 to December 31 years of data 2012.Analisa univariate and bivariate statistical Chi - Square test with significance level α = 0.05 . The results showed there were 80 respondents ( 46.3 % ) who became MOW contraceptive acceptors , acceptors who have old age by 45 respondents ( 56.3 % ) and who has a young age by 35 respondents ( 43.8 % ) . acceptors which have high parity were 44 respondents ( 55 % ) who had low parity and a total of 36 respondents ( 45 % ) . From the results of Chi-square test value obtained ρ = 0.00 is smaller than α = 0.05 . There is a significant correlation between age and the selection of MOW Chi square test results obtained ρ value = 0.00 and there was a significant association between parity with the election MOW Chi square test results obtained ρ value = 0 , . From these results , it is expected to power health, especially family planning services at the hospital . Palembang Police Hospitals in order to improve the quality of family planning services in an effective, efficient , and safe are considered particularly suitable for users of contraception OperatingMethodWomen(MOW).                                      ABSTRAK Di negara sudah maju jumlah pilihan kontrasepsi mantap (kontap) sekitar 10% dari semua metode KB nasional, sedangkan di Indonesia baru mencapai sekitar 5,7 %. Berdasarkan data yang diperoleh dari Rekam medik  Rumah Sakit Bhayangkara Palembang tahun 2010 Jumlah pencapain tersebut jika dilihat dari persentasi penggunaan kontrasepsi MOW hanya  9,10% Tujuan penelitian ini adalah diketahuinya hubungan umur dan paritas dengan pemilihan alat kontrasepsi Metode Operasi Wanita (MOW) di poliklinik kebidanan RS.Bhayangkara Palembang Tahun 2012. Penelitian ini menggunakan metode survey analitik dengan pendekatan cross sectional. Populasi dalam penelitian ini adalah wanita yang menjadi akseptor KB Baru yang tercatat di rekam medik  di RS. Bhayangkara Palembang tanggal 1 januari 2012 sampai dengan 31 Desember  tahun 2012. Sampel dalam penelitian ini adalah sebagian dari seluruh jumlah akseptor KB Baru (baik yang menggunakan alat kontrasepsi Metode MOW maupun Metode KB lain) yang teregister di RS. Bhayangkara Palembang dari tanggal 1 januari 2012 sampai dengan 31 Desember  tahun 2012.Analisa data dilakukan secara univariat dan bivariat dengan uji statistik Chi-Square dengan tingkat kemaknaan α = 0,05. Hasil penelitian menunjukkan dari 80 responden terdapat (46,3%) yang menjadi akseptor kontrasepsi MOW, akseptor yang memiliki umur tua sebanyak 45 responden (56,3%) dan yang memiliki  umur muda sebanyak 35 responden (43,8%). akseptor yang memiliki paritas tinggi sebanyak 44 responden  (55%) dan yang memiliki  paritas rendah sebanyak 36 responden (45%). Dari hasil uji Chi square didapatkan ρ value = 0,00 lebih kecil dari α = 0,05. Ada hubungan yang bermakna antara umur dengan pemilihan MOW dari hasil uji Chi square didapatkan ρ value = 0,00 dan ada hubungan yang bermakna antara paritas dengan pemilihan MOW hasil uji Chi square didapatkan ρ value = 0,.Dari hasil penelitian ini, diharapkan kepada tenaga kesehatan khususnya pelayanan KB  di RS. Bhayangkara Palembang  agar dapat meningkatkan kualitas pelayanan KB secara efektif, efisien, dan aman yang dianggap cocok bagi penggunanya khususnya mengenai kontrasepsi Metode Operasi Wanita (MOW).    

Sunlight exposure: the effects on the performance of paragliding fabric

2018 ◽  
Vol 69 (05) ◽  
pp. 381-389
Author(s):  
MENGÜÇ GAMZE SÜPÜREN ◽  
TEMEL EMRAH ◽  
BOZDOĞAN FARUK
Keyword(s):  
Mechanical Properties ◽  
Aging Process ◽  
Air Permeability ◽  
Sunlight Exposure ◽  
Test Results ◽  
Coating Materials ◽  
Strength Tests ◽  
Before And After ◽  
The Relationship ◽  
Dark Blue

This study was designed to explore the relationship between sunlight exposure and the mechanical properties of paragliding fabrics which have different colors, densities, yarn counts, and coating materials. This study exposed 5 different colors of paragliding fabrics (red, turquoise, dark blue, orange, and white) to intense sunlight for 150 hours during the summer from 9:00 a.m. to 3:00 p.m. for 5 days a week for 5 weeks. Before and after the UV radiation aging process, the air permeability, tensile strength, tear strength, and bursting strength tests were performed. Test results were also evaluated using statistical methods. According to the results, the fading of the turquoise fabric was found to be the highest among the studied fabrics. It was determined that there is a significant decrease in the mechanical properties of the fabrics after sunlight exposure. After aging, the fabrics become considerably weaker in the case of mechanical properties due to the degradation in both the dyestuff and macromolecular structure of the fiber

Selection of one-dimensional sedimentation: models for on-line use

1995 ◽  
Vol 31 (2) ◽  
pp. 193-204 ◽  
Author(s):  
Koen Grijspeerdt ◽  
Peter Vanrolleghem ◽  
Willy Verstraete
Keyword(s):  
Steady State ◽  
Selection Criteria ◽  
Data Sets ◽  
Concentration Profiles ◽  
A Posteriori ◽  
One Dimensional ◽  
On Line ◽  
Dynamic Concentration ◽  
Selection Of ◽  
Modelling Task

A comparative study of several recently proposed one-dimensional sedimentation models has been made. This has been achieved by fitting these models to steady-state and dynamic concentration profiles obtained in a down-scaled secondary decanter. The models were evaluated with several a posteriori model selection criteria. Since the purpose of the modelling task is to do on-line simulations, the calculation time was used as one of the selection criteria. Finally, the practical identifiability of the models for the available data sets was also investigated. It could be concluded that the model of Takács et al. (1991) gave the most reliable results.

Elaboration and Characterization of the Properties of Refractory Cr Base Alloys

2010 ◽  
Vol 72 ◽  
pp. 46-52 ◽  
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.

scholarly journals Advances in Fabricating the Electrospun Biopolymer-Based Biomaterials

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.

Sign in / Sign up

Export Citation Format

Share Document