Ibrahim, Omar Mohamed Omar;Heniegal, Ashraf Mohamed;Ibrahim, Khamis Gamal;Agwa, Ibrahim Saad
Advances in concrete construction
/
제10권5호
/
pp.455-462
/
2020
This study investigated the effect of horizontal casting joints on the mechanical properties and structural behavior of sustainable self-compacting reinforced concrete beams (SCRCB). The experimental research consisted of two stages. The first stage used four types of concrete mixtures which were produced to indicate the effects of cement replaced with cement waste at 0%, 5%, 10%, and 15% by weight of cement content on fresh concrete properties of self-compacting concrete (SCC) such as, passing ability, filling ability, and segregation resistance. In addition, mechanical properties such as compressive, tensile, and flexural strength were also studied. The second stage selected the best mixture from the first stage and studied the effect of horizontal casting joints on the structural behavior of sustainable SCRCBs. The effect of horizontal casting joints on the mechanical properties and structural behavior were at the 25%, 50%, 75%, and 100% of sample height. Load deflection, failure mode, and theoretical analysis were studied. Results indicated that the incorporation of replacement with cement waste by 5% to 10% led to economic and environmental advantages, and the results were acceptable for fresh and mechanical properties. The results indicated that delaying the time for casting the second layer and increasing the cement waste in concrete mixtures had a great effect on the mechanical properties of SCC. The ultimate load capacity of horizontal casting joints reinforced concrete beams slightly decreased compared with the control beam. The maximum deflection of casting joint beams with 75% of samples height is similar with the control beam. The experimental results of reinforced concrete beams were substantially acceptable with the theoretical results. The failure modes obtained the best forced casting joint on the structural behavior at 50% height of casting in the beam.
This paper describes the development and fabrication of a high temperature superconducting motor which consists of HTS rotor and air-core stator. The machine was designed for the rated power of 100hp at 1800 rpm. The HTS field windings are composed of the double-pancake coils wound with AMSC's SUS-reinforced Bi-2223 tape conductor. These were assembled on the support structure and fixed by a bandage of glass-fiber composite. The cooling system is based on the heat transfer mechanism of the thermosyphon by using GM cryocooler as cooling source. The cold head is in contact with the condenser of a Ne-filled thermosyphon. The rotor assembly was tested independently at the stationary state and combined with stator. Characteristic parameters such as reactances, inductances, and time constants were determined to obtain a consistent overview of the machine operation properties. This motor has met all design parameters by demonstrating HTS field winding, cryogenic refrigeration systems and an air-core armature winding cooled with air. The HTS field winding could be cooled down below 30K. No-load test of open-circuit characteristics(OCC) and short-circuit characteristics(SCC) and load test with resistive load bank were conducted in generator mode. Maximum operating current of field winding at 30K was 120A. From OCC and SCC test results synchronous inductance and synchronous reactance were 2.4mH, 0.49pu, respectively. Efficiency of this HTS machine was 93.3% in full load(100hp) test. This paper will present design, construction, and basic experimental test results of the 100hp HTS machine.
Gulsan, Mehmet Eren;Al Jawahery, Mohammed S.;Alshawaf, Adnan H.;Hussein, Twana A.;Abdulhaleem, Khamees N.;Cevik, Abdulkadir
Advances in concrete construction
/
제6권5호
/
pp.423-463
/
2018
This paper investigates the behavior of normal and self-compacted steel fiber reinforced concrete (SCC-SFRC) corbels rehabilitated by Basalt Fiber Mesh (BFM) and Basalt Fiber Fabric (BFF) for the first time in literature. The research objective is to study the effectiveness of BFM and BFF in the rehabilitation of damaged reinforced concrete corbels with and without epoxy injection. The experimental program includes two types of concrete: normal concrete, and self-compacted concrete. For normal concrete, 12 corbels were rehabilitated by BFM without injection epoxy in cracks, with two values of compressive strength, three ratios of steel fiber (SF), and two values of shear span. For self-compacted concrete, 48 corbels were rehabilitated with different parameters where 12 corbels were rehabilitated by BFM with and without epoxy injection, 18 heated corbels with three different high-temperature level were rehabilitated by repairing cracks only by epoxy injection, and 18 heated corbels with three different high-temperature level were rehabilitated by repairing cracks by epoxy and wrapping by BFF. All 48 corbels have two values of compressive strength, three values volumetric ratios of SF, and two values of the shear span. Test results indicate that RC corbels rehabilitated by BFM only without injection did not show any increase in the ultimate load capacity. Moreover, For RC corbels that were repaired by epoxy without basalt wrapping, the ultimate load capacities showed an increase depending on the mode of failure of corbels before the rehabilitation. However, the rehabilitation with only crack repairing by epoxy injection is more effective on medium strength corbels as compared to high strength ones. Finally, it can be concluded that use of BFF is an effective and powerful technique for the strengthening of damaged RC corbels.
The use of multi scale modeling concepts and simulation techniques to study the destabilization of an ultrathin layer of oxide interface between a metal substrate and the surrounding environment is considered. Of particular interest are chemo-mechanical behavior of this interface in the context of a molecular-level description of stress corrosion cracking. Motivated by our previous molecular dynamics simulations of unit processes in materials strength and toughness, we examine the challenges of dealing with chemical reactivity on an equal footing with mechanical deformation, (a) understanding electron transfer processes using first-principles methods, (b) modeling cation transport and associated charged defect migration kinetics, and (c) simulation of pit nucleation and intergranular deformation to initiate the breakdown of the oxide interlayer. These problems illustrate a level of multi-scale complexity that would be practically impossible to attack by other means; they also point to a perspective framework that could guide future research in the broad computational science community.
Constituents of animal biofluids such as milk, blood and urine contain information specifically related to metabolic and health status of the ruminant animals. Some changes in composition of biofluids can be attributed to disease response of the animals. Mastitis is a major problem for the global dairy industry and causes substantial economic losses from decreasing milk production and reducing milk quality. The purpose of this study was to investigate potential of NIRS combined with multivariate analysis for cow's mastitis diagnosis based on NIR spectra of milk, blood and urine. A total of 112 bulk milk, urine and blood samples from 4 Holstein cows were analyzed. The milk samples were collected from morning milking. The urine samples were collected before morning milking and stored at -35$^{\circ}C$ until spectral analysis. The blood samples were collected before morning milking using a catheter inserted into the carotid vein. Heparin was added to blood samples to prevent coagulation. All milk samples were analyzed for somatic cell count (SCC). The SCC content in milk was used as indicator of mastitis and as quantitative parameter for respective urine and blood samples collected at same time. NIR spectra of blood and milk samples were obtained by InfraAlyzer 500 spectrophotometer, using a transflectance mode. NIR spectra of urine samples were obtained by NIR System 6500 spectrophotometer, using 1 mm sample thickness. All samples were divided into calibration set and test set. Class variable was assigned for each sample as follow: healthy (class 1) and mastitic (class 2), based on milk SCC content. SIMCA was implemented to create models of the respective classes based on NIR spectra of milk, blood or urine. For the calibration set of samples, SIMCA models (model for samples from healthy cows and model for samples from mastitic cows), correctly classified from 97.33 to 98.67% of milk samples, from 97.33 to 98.61% of urine samples and from 96.00 to 94.67% of blood samples. From samples in the test set, the percent of correctly classified samples varied from 70.27 to 89.19, depending mainly on spectral data pretreatment. The best results for all data sets were obtained when first derivative spectral data pretreatment was used. The incorrect classified samples were 5 from milk samples,5 and 4 from urine and blood samples, respectively. The analysis of changes in the loading of first PC factor for group of samples from healthy cows and group of samples from mastitic cows showed, that separation between classes was indirect and based on influence of mastitis on the milk, blood and urine components. Results from the present investigation showed that the changes that occur when a cow gets mastitis influence her milk, urine and blood spectra in a specific way. SIMCA allowed extraction of available spectral information from the milk, urine and blood spectra connected with mastitis. The obtained results could be used for development of a new method for mastitis detection.
A comparative DNS study of the ignition characteristics of dual-fueled reactivity controlled compression ignition (RCCI) and stratification charge compression ignition (SCCI) is investigated using a 116-species reduced primary reference fuel (PRF) mechanism. In the RCCI combustion, two PRF fuels (n-heptane and iso-octane) with opposite autoignition characteristics are separatedly supplied and in-cylinder blended such that spatial variations in fuel reactivity, fuel concentration and temperature are achieved. In the SCCI combustion, however, just a single fuel (PRF50) is used such that only fuel concentration and temperature inhomoginieties are obtained. Because three factors, rather than only two as in SCCI combustion, govern the overall RCCI combustion, combustion timing and combustion duration or heat release rate of RCCI combustion are flexibly and effectively controlled. It is found that the overall RCCI combustion occurs much earlier and its combustion duration is longer compared to SCC combustionI. Moreover, the negative temperature coefficient (NTC) has a positive effect on enhancing RCCI combustion by inducing a shorter combustion timing and a longer combustion duration as a result of the occurrence of a predominant low-speed deflagration-combustion mode.
This paper suggests a car-following algorithm for urban environment, with multiple target candidates. Until now, advanced driver assistant systems (ADASs) and self-driving technologies have been researched to cope with diverse possible scenarios. Among them, car-following driving has been formed the groundwork of autonomous vehicle for its integrity and flexibility to other modes such as smart cruise system (SCC) and platooning. Although the field has a rich history, most researches has been focused on the shape of target trajectory, such as the order of interpolated polynomial, in simple single-lane situation. However, to introduce the car-following mode in urban environment, realistic situation should be reflected: multi-lane road, target's unstable driving tendency, obstacles. Therefore, the suggested car-following system includes both in-lane preceding vehicle and other factors such as side-lane targets. The algorithm is comprised of three parts: path candidate generation and optimal trajectory selection. In the first part, initial guesses of desired paths are calculated as polynomial function connecting host vehicle's state and vicinal vehicle's predicted future states. In the second part, final target trajectory is selected using quadratic cost function reflecting safeness, control input efficiency, and initial objective such as velocity. Finally, adjusted path and control input are calculated using model predictive control (MPC). The suggested algorithm's performance is verified using off-line simulation using Matlab; the results shows reasonable car-following motion planning.
Staphylococcus aureus is one of most prevalent intramammary pathogens and have characteristics which are not easily eradicated. Recently, to understand the sources and transmission of S aureus, many studies have focused on the subtyping of field isolate. This study was preformed to investigate the distribution pattern and characteristics of the isolates using phenotyping and genotyping. Samples were collected from milk of each udder, cow bodies (perianal region, vagina, tail, udder skin, sole) and environment (floor, liner, milker's hands, water, towel, insect) from 6 herds located in Kyung-gi province. Forty five strains of S aureus were isolated from 3 dairy herds (A, B, C) and were typed by hemolytic pattern, antibiotic resistant pattern, enterotoxin typing and PCR-based DNA fingerprinting. Slime productivity was also compared by each subtype to examine potential infectiousness. Of 45 strains, 41 were isolated from milk samples and 4 were isolated from liners. No strains isolated in the bodies and environment. Forty five strains isolated were classified as 18 subtypes by phenotyping and genotyping. There was common subtype between A and B herd, but the subtype of C herd showed different pattern. Among predominant subtypes, 60% of S aureus strain isolated from A and B herd showed subtype I and 50% of S aureus strain isolated from C herd belonged to subtype VI and X II. Neither somatic cell count (SCC) nor slime production was significantly different between predominant and minor subtypes. In summary, the study revealed that liners play more important roles in the mode of transmission than environmental sources. Several subtypes can be found in a herd, only a few subtype, however, was largely associated with the majority of infection.
Background: Aberrant microRNA expression has been associated with the pathogenesis of a variety of human malignancies including oral squamous cell carcinoma (SCC). In this study, we examined primary oral SCCs for the expression of 6 candidate miRNAs, of which five (miR-34a, miR-143, miR-373, miR-380-5p, and miR-504) regulate the tumor suppressor TP53 and one (miR-99a) is involved in AKT/mTOR signaling. Materials and Methods: Tumor tissues (punch biopsies) were collected from 52 oral cancer patients and as a control, 8 independent adjacent normal tissue samples were also obtained. After RNA isolation, we assessed the mature miRNA levels of the 6 selected candidates against RNU44 and RNU48 as endogenous controls, using specific TaqMan miRNA assays. Results: miR-34a, miR-99a, miR-143 and miR-380-5p were significantly down-regulated in tumors compared to controls. Moreover, high levels of miR-34a were associated with alcohol consumption while those of miR-99a and miR-143 were associated with advanced tumor size. No significant difference was observed in the levels of miR-504 between the tumors and controls whereas miR-373 was below the detection level in all but two tumor samples. Conclusions: Low levels of miR-380-5p and miR-504 that directly target the 3'UTR of TP53 suggest that p53 may not be repressed by these two miRNAs in OSCC. On the other hand, low levels of miR-34a or miR-143 may relieve MDM4 and SIRT1 or MDM2 respectively, which will sequester p53 indicating an indirect mode of p53 suppression in oral tumors.
본 웹사이트에 게시된 이메일 주소가 전자우편 수집 프로그램이나
그 밖의 기술적 장치를 이용하여 무단으로 수집되는 것을 거부하며,
이를 위반시 정보통신망법에 의해 형사 처벌됨을 유념하시기 바랍니다.
[게시일 2004년 10월 1일]
이용약관
제 1 장 총칙
제 1 조 (목적)
이 이용약관은 KoreaScience 홈페이지(이하 “당 사이트”)에서 제공하는 인터넷 서비스(이하 '서비스')의 가입조건 및 이용에 관한 제반 사항과 기타 필요한 사항을 구체적으로 규정함을 목적으로 합니다.
제 2 조 (용어의 정의)
① "이용자"라 함은 당 사이트에 접속하여 이 약관에 따라 당 사이트가 제공하는 서비스를 받는 회원 및 비회원을
말합니다.
② "회원"이라 함은 서비스를 이용하기 위하여 당 사이트에 개인정보를 제공하여 아이디(ID)와 비밀번호를 부여
받은 자를 말합니다.
③ "회원 아이디(ID)"라 함은 회원의 식별 및 서비스 이용을 위하여 자신이 선정한 문자 및 숫자의 조합을
말합니다.
④ "비밀번호(패스워드)"라 함은 회원이 자신의 비밀보호를 위하여 선정한 문자 및 숫자의 조합을 말합니다.
제 3 조 (이용약관의 효력 및 변경)
① 이 약관은 당 사이트에 게시하거나 기타의 방법으로 회원에게 공지함으로써 효력이 발생합니다.
② 당 사이트는 이 약관을 개정할 경우에 적용일자 및 개정사유를 명시하여 현행 약관과 함께 당 사이트의
초기화면에 그 적용일자 7일 이전부터 적용일자 전일까지 공지합니다. 다만, 회원에게 불리하게 약관내용을
변경하는 경우에는 최소한 30일 이상의 사전 유예기간을 두고 공지합니다. 이 경우 당 사이트는 개정 전
내용과 개정 후 내용을 명확하게 비교하여 이용자가 알기 쉽도록 표시합니다.
제 4 조(약관 외 준칙)
① 이 약관은 당 사이트가 제공하는 서비스에 관한 이용안내와 함께 적용됩니다.
② 이 약관에 명시되지 아니한 사항은 관계법령의 규정이 적용됩니다.
제 2 장 이용계약의 체결
제 5 조 (이용계약의 성립 등)
① 이용계약은 이용고객이 당 사이트가 정한 약관에 「동의합니다」를 선택하고, 당 사이트가 정한
온라인신청양식을 작성하여 서비스 이용을 신청한 후, 당 사이트가 이를 승낙함으로써 성립합니다.
② 제1항의 승낙은 당 사이트가 제공하는 과학기술정보검색, 맞춤정보, 서지정보 등 다른 서비스의 이용승낙을
포함합니다.
제 6 조 (회원가입)
서비스를 이용하고자 하는 고객은 당 사이트에서 정한 회원가입양식에 개인정보를 기재하여 가입을 하여야 합니다.
제 7 조 (개인정보의 보호 및 사용)
당 사이트는 관계법령이 정하는 바에 따라 회원 등록정보를 포함한 회원의 개인정보를 보호하기 위해 노력합니다. 회원 개인정보의 보호 및 사용에 대해서는 관련법령 및 당 사이트의 개인정보 보호정책이 적용됩니다.
제 8 조 (이용 신청의 승낙과 제한)
① 당 사이트는 제6조의 규정에 의한 이용신청고객에 대하여 서비스 이용을 승낙합니다.
② 당 사이트는 아래사항에 해당하는 경우에 대해서 승낙하지 아니 합니다.
- 이용계약 신청서의 내용을 허위로 기재한 경우
- 기타 규정한 제반사항을 위반하며 신청하는 경우
제 9 조 (회원 ID 부여 및 변경 등)
① 당 사이트는 이용고객에 대하여 약관에 정하는 바에 따라 자신이 선정한 회원 ID를 부여합니다.
② 회원 ID는 원칙적으로 변경이 불가하며 부득이한 사유로 인하여 변경 하고자 하는 경우에는 해당 ID를
해지하고 재가입해야 합니다.
③ 기타 회원 개인정보 관리 및 변경 등에 관한 사항은 서비스별 안내에 정하는 바에 의합니다.
제 3 장 계약 당사자의 의무
제 10 조 (KISTI의 의무)
① 당 사이트는 이용고객이 희망한 서비스 제공 개시일에 특별한 사정이 없는 한 서비스를 이용할 수 있도록
하여야 합니다.
② 당 사이트는 개인정보 보호를 위해 보안시스템을 구축하며 개인정보 보호정책을 공시하고 준수합니다.
③ 당 사이트는 회원으로부터 제기되는 의견이나 불만이 정당하다고 객관적으로 인정될 경우에는 적절한 절차를
거쳐 즉시 처리하여야 합니다. 다만, 즉시 처리가 곤란한 경우는 회원에게 그 사유와 처리일정을 통보하여야
합니다.
제 11 조 (회원의 의무)
① 이용자는 회원가입 신청 또는 회원정보 변경 시 실명으로 모든 사항을 사실에 근거하여 작성하여야 하며,
허위 또는 타인의 정보를 등록할 경우 일체의 권리를 주장할 수 없습니다.
② 당 사이트가 관계법령 및 개인정보 보호정책에 의거하여 그 책임을 지는 경우를 제외하고 회원에게 부여된
ID의 비밀번호 관리소홀, 부정사용에 의하여 발생하는 모든 결과에 대한 책임은 회원에게 있습니다.
③ 회원은 당 사이트 및 제 3자의 지적 재산권을 침해해서는 안 됩니다.
제 4 장 서비스의 이용
제 12 조 (서비스 이용 시간)
① 서비스 이용은 당 사이트의 업무상 또는 기술상 특별한 지장이 없는 한 연중무휴, 1일 24시간 운영을
원칙으로 합니다. 단, 당 사이트는 시스템 정기점검, 증설 및 교체를 위해 당 사이트가 정한 날이나 시간에
서비스를 일시 중단할 수 있으며, 예정되어 있는 작업으로 인한 서비스 일시중단은 당 사이트 홈페이지를
통해 사전에 공지합니다.
② 당 사이트는 서비스를 특정범위로 분할하여 각 범위별로 이용가능시간을 별도로 지정할 수 있습니다. 다만
이 경우 그 내용을 공지합니다.
제 13 조 (홈페이지 저작권)
① NDSL에서 제공하는 모든 저작물의 저작권은 원저작자에게 있으며, KISTI는 복제/배포/전송권을 확보하고
있습니다.
② NDSL에서 제공하는 콘텐츠를 상업적 및 기타 영리목적으로 복제/배포/전송할 경우 사전에 KISTI의 허락을
받아야 합니다.
③ NDSL에서 제공하는 콘텐츠를 보도, 비평, 교육, 연구 등을 위하여 정당한 범위 안에서 공정한 관행에
합치되게 인용할 수 있습니다.
④ NDSL에서 제공하는 콘텐츠를 무단 복제, 전송, 배포 기타 저작권법에 위반되는 방법으로 이용할 경우
저작권법 제136조에 따라 5년 이하의 징역 또는 5천만 원 이하의 벌금에 처해질 수 있습니다.
제 14 조 (유료서비스)
① 당 사이트 및 협력기관이 정한 유료서비스(원문복사 등)는 별도로 정해진 바에 따르며, 변경사항은 시행 전에
당 사이트 홈페이지를 통하여 회원에게 공지합니다.
② 유료서비스를 이용하려는 회원은 정해진 요금체계에 따라 요금을 납부해야 합니다.
제 5 장 계약 해지 및 이용 제한
제 15 조 (계약 해지)
회원이 이용계약을 해지하고자 하는 때에는 [가입해지] 메뉴를 이용해 직접 해지해야 합니다.
제 16 조 (서비스 이용제한)
① 당 사이트는 회원이 서비스 이용내용에 있어서 본 약관 제 11조 내용을 위반하거나, 다음 각 호에 해당하는
경우 서비스 이용을 제한할 수 있습니다.
- 2년 이상 서비스를 이용한 적이 없는 경우
- 기타 정상적인 서비스 운영에 방해가 될 경우
② 상기 이용제한 규정에 따라 서비스를 이용하는 회원에게 서비스 이용에 대하여 별도 공지 없이 서비스 이용의
일시정지, 이용계약 해지 할 수 있습니다.
제 17 조 (전자우편주소 수집 금지)
회원은 전자우편주소 추출기 등을 이용하여 전자우편주소를 수집 또는 제3자에게 제공할 수 없습니다.
제 6 장 손해배상 및 기타사항
제 18 조 (손해배상)
당 사이트는 무료로 제공되는 서비스와 관련하여 회원에게 어떠한 손해가 발생하더라도 당 사이트가 고의 또는 과실로 인한 손해발생을 제외하고는 이에 대하여 책임을 부담하지 아니합니다.
제 19 조 (관할 법원)
서비스 이용으로 발생한 분쟁에 대해 소송이 제기되는 경우 민사 소송법상의 관할 법원에 제기합니다.
[부 칙]
1. (시행일) 이 약관은 2016년 9월 5일부터 적용되며, 종전 약관은 본 약관으로 대체되며, 개정된 약관의 적용일 이전 가입자도 개정된 약관의 적용을 받습니다.