Seismic Behavior of Horizontally Irregular Structures: Current Wisdom and Challenges Ahead

2016 ◽  
Vol 68 (6) ◽  
Author(s):  
Suvonkar Chakroborty ◽  
Rana Roy

In view of the stronger vulnerability of horizontally irregular structures during earthquakes, numerous studies have been made since mid-1950 s. Unfortunately, research progress in this subject does not appear encouraging. This is evident from the current wisdom embodied in modern codes in the form of design guidelines. Beginning with a critical review of the earlier works and the available code-provisions, the present paper emphasizes on the prevalent controversies and the fundamental fallacies in research studies and traditional design. The review intends to address the strength vis-a-vis weakness of the studies accomplished so far and helps streamlining future research. The present paper also summarizes the updated views for selecting and processing appropriate set of ground motions. This is a key input in seismic response assessment and a major reason of the existing controversies in the subject of asymmetry. A prognostic scrutiny of the research progress recognizes the prospective challenges ahead.

2002 ◽  
Vol 18 (1) ◽  
pp. 121-142 ◽  
Author(s):  
Ayman A. Shama ◽  
John B. Mander ◽  
Blaise A. Blabac ◽  
Stuart S. Chen

The main objective of this study is to assess the seismic vulnerability of a class of highway bridges existing in certain regions of the eastern and central states, where steel H-piles extends out of the soil to support the pier cap. During severe ground motions, the overall performance of the bridge will be governed by the local performance of the pile-to-cap beam connection. The scope of work was divided into several tasks as follows: (1) a theory was developed to predict the performance of the connection under lateral loading; (2) an initial experimental program was conducted to investigate the seismic behavior of the steel bents; (3) a retrofit strategy is proposed; (4) a second experimental study was carried out to validate the proposed retrofit method; and (5) fragility curves for such structures were developed. This paper deals with the first two tasks of the study. The other three tasks are the subject of a second companion paper (Shama 2002).


Author(s):  
Muhammad Yousaf ◽  
Petr Bris

A systematic literature review (SLR) from 1991 to 2019 is carried out about EFQM (European Foundation for Quality Management) excellence model in this paper. The aim of the paper is to present state of the art in quantitative research on the EFQM excellence model that will guide future research lines in this field. The articles were searched with the help of six strings and these six strings were executed in three popular databases i.e. Scopus, Web of Science, and Science Direct. Around 584 peer-reviewed articles examined, which are directly linked with the subject of quantitative research on the EFQM excellence model. About 108 papers were chosen finally, then the purpose, data collection, conclusion, contributions, and type of quantitative of the selected papers are discussed and analyzed briefly in this study. Thus, this study identifies the focus areas of the researchers and knowledge gaps in empirical quantitative literature on the EFQM excellence model. This article also presents the lines of future research.


2020 ◽  
Vol 21 (13) ◽  
pp. 996-1008
Author(s):  
Mengli Wang ◽  
Qiuzheng Du ◽  
Lihua Zuo ◽  
Peng Xue ◽  
Chao Lan ◽  
...  

Background: As a new tumor therapy, targeted therapy is becoming a hot topic due to its high efficiency and low toxicity. Drug effects of targeted tumor drugs are closely related to pharmacokinetics, so it is important to understand their distribution and metabolism in vivo. Methods: A systematic review of the literature on the metabolism and distribution of targeted drugs over the past 20 years was conducted, and the pharmacokinetic parameters of approved targeted drugs were summarized in combination with the FDA's drug instructions. Targeting drugs are divided into two categories: small molecule inhibitors and monoclonal antibodies. Novel targeting drugs and their mechanisms of action, which have been developed in recent years, are summarized. The distribution and metabolic processes of each drug in the human body are reviewed. Results: In this review, we found that the distribution and metabolism of small molecule kinase inhibitors (TKI) and monoclonal antibodies (mAb) showed different characteristics based on the differences of action mechanism and molecular characteristics. TKI absorbed rapidly (Tmax ≈ 1-4 h) and distributed in large amounts (Vd > 100 L). It was mainly oxidized and reduced by cytochrome P450 CYP3A4. However, due to the large molecular diameter, mAb was distributed to tissues slowly, and the volume of distribution was usually very low (Vd < 10 L). It was mainly hydrolyzed and metabolized into peptides and amino acids by protease hydrolysis. In addition, some of the latest drugs are still in clinical trials, and the in vivo process still needs further study. Conclusion: According to the summary of the research progress of the existing targeting drugs, it is found that they have high specificity, but there are still deficiencies in drug resistance and safety. Therefore, the development of safer and more effective targeted drugs is the future research direction. Meanwhile, this study also provides a theoretical basis for clinical accurate drug delivery.


2019 ◽  
Vol 14 ◽  
Author(s):  
Khaleel Ahmad ◽  
Afsar Kamal

Background: Privacy enhancing techniques are developed in order to provide strong protection to cyberspace. These techniques aim to allow users to keep their identities hidden during the communication when they are sending email, making payments online, browsing the Web or posting to newsgroups. MixNet is the most practical solution for concealing identities of message and sender’s identities. Objective: It provides sender and receiver anonymity as well as message security. The main goal of MixNet is to overcome vulnerability and enhance the performance of communication. It can efficiently handle the messages of various length and produce desirable results with privacy. The main objective of this paper is to acquire information and concepts regarding MixNet. We also provide guidelines for future research and references. Methods : The designing of MixNet depends on what cryptosystem method is used. Symmetric and Asymmetric both are used. Other methods could be also used such as PIR, CSP and FDR model, RPC, Token-based approach or others. Result: In this paper we provide an overview of MixNet approaches and presented a survey on MixNet based techniques and different models. We also constructed the comparison tables as per our requirements for better understanding. For this purpose, we found a total of 120 articles related to the MixNet published between 1990 and 2018 from the most relevant scientific resources. However, only 86 papers were analyzed due to comprehensiveness and relevancy to this article. Conclusion: Focused on the security and privacy of communication and how it can be achieved. This survey also reveals research progress and research gap on MixNet.


2021 ◽  
pp. 028418512110198
Author(s):  
Frank Mosler ◽  
Johannes K Richter ◽  
Marc Schindewolf ◽  
Nando Mertineit ◽  
Hendrik von Tengg-Kobligk ◽  
...  

X-ray contrast media have been reported to have inhibitory effects on bacterial growth. Despite its potentially beneficial effect on patients, these features of contrast media have received relatively little attention in the medical literature in the past decades. The aim of this review is to evaluate the literature concerning the bactericidal and bacteriostatic effects of X-ray contrast media, specifically if there is a known difference concerning these effects between ionic and non-ionic contrast media. Systematic literature review was performed for the years of publication between 1911 and 2019. Since the publication of Grossich in 1911, the effect of iodine on the treatment of superficial infections in surgical procedures has been established clinical knowledge. Bacteriostatic and bactericidal effects of ionic X-ray contrast media are well established. However, non-ionic contrast agents have been the subject of little research in this respect. In past decades, the hypothesis emerged in the literature that mainly the concentration of free iodine might be responsible for any bacteriostatic or bactericidal effect of ionic X-ray contrast media. Nowadays, however, only non-ionic contrast media are used. The question regarding the mechanism and magnitude of bacteriostatic or bactericidal effects of these, non-ionic contrast media, could not be answered conclusively from this review. Non-ionic contrast media could be used intentionally when a local antibacterial effect is intended (e.g. in percutaneous abscess drainage), as well as to reduce the overall dose of antibiotics administered to a patient. Thus, this question remains relevant and might constitute the area of future research.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3530
Author(s):  
Fukang Ma ◽  
Shuanlu Zhang ◽  
Zhenfeng Zhao ◽  
Yifang Wang

The hydraulic free-piston engine (HFPE) is a kind of hybrid-powered machine which combines the reciprocating piston-type internal combustion engine and the plunger pump as a whole. In recent years, the HFPE has been investigated by a number of research groups worldwide due to its potential advantages of high efficiency, energy savings, reduced emissions and multi-fuel operation. Therefore, our study aimed to assess the operating characteristics, core questions and research progress of HFPEs via a systematic review and meta-analysis. We included operational control, starting characteristics, misfire characteristics, in-cylinder working processes and operating stability. We conducted the literature search using electronic databases. The research on HFPEs has mainly concentrated on four kinds of free-piston engine, according to piston arrangement form: single piston, dual pistons, opposed pistons and four-cylinder complex configuration. HFPE research in China is mainly conducted in Zhejiang University, Tianjin University, Jilin University and the Beijing Institute of Technology. In addition, in China, research has mainly focused on the in-cylinder combustion process while a piston is free by considering in-cylinder combustion machinery and piston dynamics. Regarding future research, it is very important that we solve the instabilities brought about by chance fluctuations in the combustion process, which will involve the hydraulic system’s efficiency, the cyclical variation, the method of predicting instability and the recovery after instability.


Author(s):  
Temel Türker ◽  
Betül Demirtaş ◽  
Ali Ural ◽  
Mehmet Aydın Kömür

2021 ◽  
Vol 13 (13) ◽  
pp. 7217
Author(s):  
Zhen Liu ◽  
Jing Liu ◽  
Mohamed Osmani

Circular economy (CE) is a concept actively advocated by the European Union (EU), China, Japan, and the United Kingdom. At present, CE is considered to grant the most traction for companies to achieve sustainable development. However, CE is still rarely adopted by enterprises. As the backbone of the fourth industrial revolution, the digital economy (DE) is considered to have a disruptive effect. Studies have shown that digital technology has great potential in promoting the development of CE. Especially during the COVID-19 epidemic that has severely negatively affected the global economy, environment, and society, CE and DE are receiving high attention from policy makers, practitioners, and scholars around the world. However, the integration of CE and digital technology is a small and rapidly developing research field that is still in its infancy. Although there is a large amount of research in the fields of CE and DE, respectively, there are few studies that look into integrating these two fields. Therefore, the purpose of this paper is to explore the research progress and trends of the integration of CE and DE, and provide an overview for future research. This paper adopts a bibliometric research method, employs the Web of Science database as its literature source, and uses VOSviewer visual software to carry out keyword co-occurrence analysis, which focuses on publication trends, journal sources, keyword visualization, multidisciplinary areas, life cycle stages, and application fields.


2021 ◽  
Vol 22 (12) ◽  
pp. 6222
Author(s):  
Kacper Szewczyk ◽  
Aleksandra Chojnacka ◽  
Magdalena Górnicka

Tocopherols and tocotrienols are natural compounds of plant origin, available in the nature. They are supplied in various amounts in a diet, mainly from vegetable oils, some oilseeds, and nuts. The main forms in the diet are α- and γ-tocopherol, due to the highest content in food products. Nevertheless, α-tocopherol is the main form of vitamin E with the highest tissue concentration. The α- forms of both tocopherols and tocotrienols are considered as the most metabolically active. Currently, research results indicate also a greater antioxidant potential of tocotrienols than tocopherols. Moreover, the biological role of vitamin E metabolites have received increasing interest. The aim of this review is to update the knowledge of tocopherol and tocotrienol bioactivity, with a particular focus on their bioavailability, distribution, and metabolism determinants in humans. Almost one hundred years after the start of research on α-tocopherol, its biological properties are still under investigation. For several decades, researchers’ interest in the biological importance of other forms of vitamin E has also been growing. Some of the functions, for instance the antioxidant functions of α- and γ-tocopherols, have been confirmed in humans, while others, such as the relationship with metabolic disorders, are still under investigation. Some studies, which analyzed the biological role and mechanisms of tocopherols and tocotrienols over the past few years described new and even unexpected cellular and molecular properties that will be the subject of future research.


2021 ◽  
pp. 097340822110125
Author(s):  
Cluny Mendez ◽  
Christopher L. Atkinson

The implementation of sustainability and green public procurement (GPP) initiatives in school districts has been the subject of some debate; questions over definitions and programme goals have led to inconsistency and concerns about programme achievements. The legitimacy of programmes rests not only with the announcement of policy by officials, but with adherence to policy and staff buy-in. This study examines barriers districts face, and makes recommendations based upon district experience on ways to successfully implement sustainability and GPP initiatives. A review of the literature on GPP and legitimacy in the execution of public functions within the education domain begins the study. Major components relative to best practices for GPP programmes are studied through the review of GPP-related documents from a school district in New Jersey considered as an exemplar of such programmes. Analysis of an interview with the district’s representatives suggests that, despite the normative approval such programmes receive, and widespread understanding of the rationale for pursuing such initiatives, there remain critical failings in implementation of these programmes, stemming from education, resourcing of initiatives and prioritization of green procurement in relation to other district priorities. The study concludes with lessons learned from this case, which is important given its positioning within New Jersey as an exemplar and recommendations for future research where work in this area is needed.


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