scholarly journals Horizontal push out tests on a steel-yielding demountable shear connector

2018 ◽  
Author(s):  
George Vasdravellis ◽  
Eliza Feidaki
Keyword(s):  
Concrete Slab ◽  
Shear Connector ◽  
Load Curve ◽  
Sustainable Solutions ◽  
Hollow Core Slab ◽  
Unique Shape ◽  
The One ◽  
Increased Strength ◽  
Push Out

The most common type of a steel concrete composite beam is the one using conventional welded headed studs to connect the top flange of a steel beam to the concrete slab. However, the monolithic structure between the headed studs and the concrete slab prevents the deconstruction of the beam. More sustainable solutions in construction can be achieved by developing demountable connections which allow for fully deconstruction and reuse of all structural systems. This paper presents a novel demountable shear connector for use in steel concrete composite beams in conjunction with precast hollow core slab units. The demountable connection proposed has the advantages of minimal use of in situ concrete required only in specific regions, increased ductility due to the unique shape of the shear connector and since it is not embedded in in situ concrete, it facilitates the deconstruction procedure. Ten horizontal push out tests aiming at investigating the structural performance of the demountable shear connector were carried out. The strength of the connection is predicted  using simple mechanics based on plastic beam analysis. The experimental results showed that the proposed demountable shear connector can achieve increased strength depending on the geometric characteristics of the connector, a ductile slip-load curve and a very high slip capacity. 

Behaviour of perfobond rib shear connectors: push-out tests

1992 ◽  
Vol 19 (1) ◽  
pp. 1-10 ◽  
Author(s):  
M. R. Veldanda ◽  
M. U. Hosain
Keyword(s):  
Concrete Slab ◽  
Composite Beams ◽  
Steel Beams ◽  
Shear Connector ◽  
Reinforcing Bars ◽  
Longitudinal Splitting ◽  
Shear Connectors ◽  
Beam Shear ◽  
Headed Stud ◽  
Push Out

This paper summarizes the results of tests performed on 48 push-out specimens to investigate the feasibility of using perfobond rib type shear connectors in composite beams with ribbed metal decks placed parallel to the steel beams. The perfobond rib shear connector is a flat steel plate containing a number of holes. The results indicate that perfobond rib connectors can be effectively used in composite beams with ribbed metal decks placed parallel to the steel beams. An appreciable improvement in performance was observed in test specimens when additional reinforcing bars were passed through the perfobond rib holes. Shank shear was the principal mode of failure in specimens with headed studs. In specimens with perfobond rib, failure was triggered by the longitudinal splitting of the concrete slab, followed by the crushing of concrete in front of the perfobond rib. Key words: composite beam, shear connector, perfobond rib, headed stud, push-out test, metal deck.

scholarly journals Analytical Model for Load–Slip Relationship of Perfobond Shear Connector Based on Push-Out Test

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 29 ◽  
Author(s):  
Shuangjie Zheng ◽  
Chen Zhao ◽  
Yangqing Liu
Keyword(s):  
Analytical Model ◽  
Composite Structures ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Shear Connector ◽  
Design Variables ◽  
Wide Range ◽  
Alternative Type ◽  
Relationship Of ◽  
Push Out

In composite structures, the perfobond connector is an alternative type of shear connector which consists of a steel plate with a certain number of holes. The load–slip relationship is critical for structural analysis and numerical simulation of composite structures using perfobond connectors. In this study, push-out tests were conducted on 72 specimens to obtain the load–slip behaviors of perfobond connectors. Based on the test results, parametric study was performed to analyze the effects of changing the hole geometry, the concrete strength, the configuration of the rebar in hole, the dimensions of the perfobond rib, and the size of the concrete slab. Furthermore, the characteristics and physical meanings of the load–slip curves were analyzed, and the limits and conditions for theoretical expressions were derived. Finally, an analytical model was proposed to express the load–slip relationship of perfobond connectors covering a wide range of design variables.

scholarly journals NIR responsive tumor vaccine in situ for photothermal ablation and chemotherapy to trigger robust antitumor immune responses

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Lirong Zhang ◽  
Jingjing Zhang ◽  
Lixia Xu ◽  
Zijian Zhuang ◽  
Jingjin Liu ◽  
...  
Keyword(s):  
Immune Responses ◽  
Tumor Vaccine ◽  
Oxidative Polymerization ◽  
Delivery Mode ◽  
Tumor Treatment ◽  
One Pot ◽  
Photothermal Ablation ◽  
Prolonged Retention ◽  
The One

Abstract Background Therapeutic tumor vaccine (TTV) that induces tumor-specific immunity has enormous potentials in tumor treatment, but high heterogeneity and poor immunogenicity of tumor seriously impair its clinical efficacy. Herein, a novel NIR responsive tumor vaccine in situ (HA-PDA@IQ/DOX HG) was prepared by integrating hyaluronic acid functionalized polydopamine nanoparticles (HA-PDA NPs) with immune adjuvants (Imiquimod, IQ) and doxorubicin (DOX) into thermal-sensitive hydrogel. Results HA-PDA@IQ NPs with high photothermal conversion efficiency (41.2%) and T1-relaxation efficiency were using HA as stabilizer by the one-pot oxidative polymerization. Then, HA-PDA@IQ loaded DOX via π-π stacking and mixed with thermal-sensitive hydrogel to form the HA-PDA@IQ/DOX HG. The hydrogel-confined delivery mode endowed HA-PDA@IQ/DOX NPs with multiple photothermal ablation performance once injection upon NIR irradiation due to the prolonged retention in tumor site. More importantly, this mode enabled HA-PDA@IQ/DOX NPs to promote the DC maturation, memory T cells in lymphatic node as well as cytotoxic T lymphocytes in spleen. Conclusion Taken together, the HA-PDA@IQ/DOX HG could be served as a theranostic tumor vaccine for complete photothermal ablation to trigger robust antitumor immune responses.

scholarly journals Two Separate Cases: Complex Chromosomal Abnormality Involving Three Chromosomes and Small Supernumerary Marker Chromosome in Patients with Impaired Reproductive Function

Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1511
Author(s):  
Tatyana V. Karamysheva ◽  
Tatyana A. Gayner ◽  
Vladimir V. Muzyka ◽  
Konstantin E. Orishchenko ◽  
Nikolay B. Rubtsov
Keyword(s):  
Genetic Counseling ◽  
Chromosome Rearrangement ◽  
Marker Chromosome ◽  
Reproductive Function ◽  
Small Supernumerary Marker Chromosome ◽  
Comprehensive Chromosome Screening ◽  
The Family ◽  
Multicolor Banding ◽  
The One

For medical genetic counseling, estimating the chance of a child being born with chromosome abnormality is crucially important. Cytogenetic diagnostics of parents with a balanced karyotype are a special case. Such chromosome rearrangements cannot be detected with comprehensive chromosome screening. In the current paper, we consider chromosome diagnostics in two cases of chromosome rearrangement in patients with balanced karyotype and provide the results of a detailed analysis of complex chromosomal rearrangement (CCR) involving three chromosomes and a small supernumerary marker chromosome (sSMC) in a patient with impaired reproductive function. The application of fluorescent in situ hybridization, microdissection, and multicolor banding allows for describing analyzed karyotypes in detail. In the case of a CCR, such as the one described here, the probability of gamete formation with a karyotype, showing a balance of chromosome regions, is extremely low. Recommendation for the family in genetic counseling should take into account the obtained result. In the case of an sSMC, it is critically important to identify the original chromosome from which the sSMC has been derived, even if the euchromatin material is absent. Finally, we present our view on the optimal strategy of identifying and describing sSMCs, namely the production of a microdissectional DNA probe from the sSMC combined with a consequent reverse painting.

Strengthening of a Multistory R/C Building under Lateral Loading by Utilizing Ties

2011 ◽  
Vol 82 ◽  
pp. 559-564 ◽  
Author(s):  
Olga Markogiannaki ◽  
Ioannis Tegos
Keyword(s):  
Concrete Slab ◽  
Concrete Walls ◽  
Steel Wires ◽  
Building Models ◽  
Multistory Building ◽  
Multiple Loading ◽  
Seismic Displacements ◽  
The One ◽  
Wall Method

The scope of the study is to examine of the possibility of applying steel ties, which can consist of common steel wires, as means to restrain the seismic displacements of buildings structural systems. The method seems to be competitive to the conventional ones, since fewer disturbances are created during the retrofitting works, i.e. the installation of ties as compared to the conventional strengthening methods. The method also proved to be more economic than the conventional method of constructing and infilling concrete walls in the vulnerable structural system. Initially, the efficiency of the ties was studied in multistory building models, such as frame, combined frame-wall and combined frame-wall without beams. Based on the results of the analytical study, the method was applied on a 5 storey existing and seismically deficient building. More specifically, the long side of the building was chosen for the method’s application. The last choice was deemed more preferable due to the fact that it has no openings which allowed the easy application of straight ties. The one end of the ties is anchored in the concrete slab of the upper stories, while the other end on the basement’s upper concrete slab. Although the seismic demand was higher for the implemented solution of the steel wires due to multiple loading, caused by the low value of the seismic performance coefficient equal to 1.5, an adequate level of earthquake resistance was achieved. The results of the case study confirmed the applicability of the proposed method. It should be underlined that the ties method looks promising in the field of structures retrofitting and could be studied analytically in campaigns, either independently or in combination with the conventional in concrete shear wall method.

Observing microscopic phases of lichen life cycles on transparent substrata placed in situ

2005 ◽  
Vol 37 (5) ◽  
pp. 373-382 ◽  
Author(s):  
William B. SANDERS
Keyword(s):  
Life Cycle ◽  
Developmental Stages ◽  
Life Cycles ◽  
Potential Significance ◽  
Free Living ◽  
Lichen Community ◽  
One Year ◽  
The One ◽  
Observation Period

The utility of plastic cover slips as a substratum for in situ study of lichen developmental stages is further explored in a neotropical foliicolous lichen community and in a European temperate corticolous community. Twenty-one months after placement in the tropical forest, the cover slips bore foliicolous lichen thalli with several species producing characteristic ascocarps and ascospores, indicating the suitability of the substratum for completion of the life cycle of these lichens. On cover slips placed within the temperate corticolous community, lichen propagules anchored to the substratum with relatively short attachment hyphae but did not develop further within the one year observation period. Intimately intermixed microbial communities of short-celled, mainly pigmented fungi and chlorophyte algae developed upon the transparent substratum. Among the algae, Trebouxia cells, often in groups showing cell division and without associated lichenizing hyphae, were commonly observed. The potential significance of the free-living populations in the life cycle of Trebouxia and in those of Trebouxia-associated lichen fungi is discussed.

A Domino Heck Coupling–Cyclization–Dehydrogenative Strategy for the One-Pot Synthesis of Quinolines

Synthesis ◽  
2021 ◽  
Author(s):  
Santanu Ghora ◽  
Chinnabattigalla Sreenivasulu ◽  
Gedu Satyanarayana
Keyword(s):  
Functional Group ◽  
Exchange Process ◽  
Palladium Catalysis ◽  
Allylic Alcohols ◽  
Heck Coupling ◽  
One Pot ◽  
Synthetic Process ◽  
Intramolecular Condensation ◽  
The One

AbstractAn efficient, one-pot, domino synthesis of quinolines via the coupling of iodoanilines with allylic alcohols facilitated by palladium catalysis is described. The overall synthetic process involves an intermolecular Heck coupling between 2-iodoanilines and allylic alcohols, intramolecular condensation of in situ generated ketones with an internal amine functional group, and a dehydrogenation sequence. Notably, this protocol occurs in water as a green solvent. Significantly, the method exhibits broad substrate scope and is applied for the synthesis of deuterated quinolines through a deuterium-exchange process.

Granular biomass capable of partial nitritation and anammox

2008 ◽  
Vol 58 (5) ◽  
pp. 1113-1120 ◽  
Author(s):  
S. E. Vlaeminck ◽  
L. F. F. Cloetens ◽  
M. Carballa ◽  
N. Boon ◽  
W. Verstraete
Keyword(s):  
Removal Rate ◽  
Batch Reactor ◽  
Ammonium Oxidation ◽  
Autotrophic Nitrification ◽  
Partial Nitritation ◽  
One Stage ◽  
Biomass Retention ◽  
Granular Biomass ◽  
The One

A novel and efficient way of removing nitrogen from wastewater poor in biodegradable organic carbon, is the combination of partial nitritation and anoxic ammonium oxidation (anammox), as in the one-stage oxygen-limited autotrophic nitrification/denitrification (OLAND) process. Since anoxic ammonium-oxidizing bacteria grow very slowly, maximum biomass retention in the reactor is required. In this study, a lab-scale sequencing batch reactor (SBR) was used to develop granular, rapidly settling biomass. With SBR cycles of one hour and a minimum biomass settling velocity of 0.7 m/h, OLAND granules were formed in 1.5 months and the nitrogen removal rate increased from 50 to 450 mg N L−1 d−1 in 2 months. The granules had a mean diameter of 1.8 mm and their aerobic and anoxic ammonium-oxidizing activities were well equilibrated to perform the OLAND reaction. Fluorescent in-situ hybridization (FISH) demonstrated the presence of both β-proteobacterial aerobic ammonium oxidizers and planctomycetes (among which anoxic ammonium oxidizers) in the granules. The presented results show the applicability of rapidly settling granular biomass for one-stage partial nitritation and anammox.

Field and laboratory tests were conducted (18-23), survey and review of the tests have been reported (24-26). Some correlation of theoretical and experimental data can be found in reference (27). The aforementioned brief review is limited to right (not skewed) straight (not curved) composite concrete slab on more than two steel girders type bridges. Distribution of loads for other types is being investigated under the NCHRP Project 12-26, which includes literature review and evaluation of available information. This will eventually lead to a recommended load distribution method (to replace the one that exists now) for consideration by AASHTO subcommittee on bridges and structures. The continuous portion of the bridge is about 1320 feet long, along its center line, and is composed of 6 continuous spans. The longest span is 300 feet (span 4) and it is the second continuous span from west to east (Bangor to Brewer). The spans west (span 3) and east (span 5) of the longest span are 199 feet and 247 feet respectively. The bridge is slightly curved in plan in spans 3 and 4. The bridge has 8 steel girders which are spaced at 14.0 ft. minimum to about 21 ft. maximum spacings. The girders are welded plate girders made of ASTM A588 unpainted weathering steel. The total depth of the girders in span 4 is about 10 ft. The webs are reinforced by single sided intermediate vertical stiffeners spaced at 10 to 13 ft apart. Intermediate cross-bracing diaphragms are provided between the girders at spacings vary between 17.5 and 25 feet. The bridge deck is composed of a 12 inch reinforced concrete slab which acts compositly with the steel girders (using shear connectors), and a 3 inch bituminous wearing surface. The top flange of the steel girders are embeded in the concrete and the depth of the slab over the top flange is 16 inches at the haunch. The haunch is rectangular and has a width equals the width of the steel flange plus 8 inches; 4 inches on each side of the steel flange. of the two middle girders (girder 5) was instrumented by 30 strain gages. The strain gages were Installed within span 4 (the longest span) as described in the following. Eighteen gages were installed at the location of one of the four bolted splices within the span; Six at the top flange, six

1987 ◽  
pp. 47-47
Keyword(s):  
Concrete Slab ◽  
Weathering Steel ◽  
Strain Gages ◽  
Steel Girders ◽  
Reinforced Concrete Slab ◽  
Distribution Method ◽  
Shear Connectors ◽  
The One ◽  
Available Information ◽  
Over The Top

scholarly journals REVIEW OF DIAGNOSTIC OPPORTUNITIES FOR IMPROVEMENT OF DETECTION OF NON-MUSCLE INVASIVE BLADDER CANCER

InterConf ◽  
2021 ◽  
pp. 796-803
Author(s):  
Ivan Vladanov ◽  
Alexei Plesacov ◽  
Vitalii Ghicavii
Keyword(s):  
Bladder Cancer ◽  
Narrow Band Imaging ◽  
Imaging Techniques ◽  
Meta Analysis ◽  
Photodynamic Diagnosis ◽  
White Light Cystoscopy ◽  
Carcinoma Of The Bladder ◽  
Muscle Invasive ◽  
The One

Recently white light cystoscopy (WLC) is the standard method for detection of urothelial cell carcinoma of the bladder. Regarding the problem that on the one hand the sensitivity of WLC is not high enough, and on the other hand it can miss small ‘satellite’ tumors or carcinoma in situ (CIS), other techniques are used. Such techniques are the new imaging by photodynamic diagnosis (PDD) and narrow band imaging (NBI). The both techniques allow very accurate bladder cancer visualization. It is obviously very important to improve diagnostic accuracy and as consequence it increases the quality of resection. Regarding the meta-analysis of several studies, it can be concluded that the new imaging techniques should be applied for a more precise diagnostic, comparing with WLC. Further results of multicentric meta-analysis between these two techniques will stabilize their advantages for concrete clinical indications.

Sign in / Sign up

Export Citation Format

Share Document