scholarly journals Operational characteristics of limestone and methods to increase its strength

2019 ◽  
Vol 91 ◽  
pp. 02028
Author(s):  
Elena Korneeva ◽  
Muayad Sabri Sabri Mohanad ◽  
Anna Babanina ◽  
Egor Zaytsev ◽  
Sergey Poberezhskii

Since ancient times, limestone has been known as an inexpensive and reliable building material. The main problem of limestone materials in the construction of buildings is its reduced longevity due to various factors, such as wind and rain. These factors have a huge impact on the strength characteristics of the building material, so adherence to special recommendations is an important practical task. A review of literature on the problem of durability and the use of limestone is presented. With the help of experience, the strength of nummulite limestone is established. The analysis of the obtained data is made, as well as its comparison with the indices of other artificial and natural stones. The main methods of strengthening the structures made of limestone are considered at three different stages. Practical recommendations for minimizing the impact of negative factors on this material are given.

2021 ◽  
Vol 11 (15) ◽  
pp. 6892
Author(s):  
Rina (Irena) Wasserman

The contemporary sea walls built in the pedestrian seashore zone in the City of Acre, Israel, were sided with porous calcarenite sandstone, so-called ‘kurkar’. Kurkar stone has been broadly used as a durable building material in Acre and Jaffa, the Eastern Mediterranean offshore cities, since ancient times. Therefore, the contemporary urban architectural plans obligate kurkar siding in the modern structures erected beside the Old City of Acre. However, a rapid deterioration of kurkar siding had occurred in the contemporary sea walls during only a few years. In contrast, the Historic walls built of kurkar dimensional stone have been still sound. The current study has evaluated the factors and causes of kurkar deterioration in the modern seawalls. It was revealed that the main reason for deterioration was adhering the kurkar siding with cement mortar and the next exposure of adhered siding to the humid and salt-enriched offshore environment with high air pollution.


Author(s):  
L. Mavrina ◽  
E. Shaikhlislamova ◽  
I. Khasanova ◽  
L. Karimova ◽  
N. Muldasheva ◽  
...  

The relevance of the problem. Ensuring safe working conditions is currently an urgent problem of our time. Purpose of work. Analysis of bibliographic data on issues of occupational risk, industrial injuries among workers of the processing complex. Materials and methods. To achieve this goal, materials related to this topic were studied in the works of domestic and foreign scientists. Results. A lot of scientific works are devoted to the problem of assessing professional risk in the production of a processing complex. Modern research has proved that risk assessment is one of the main methods for analyzing the impact of various production factors on an employee. Conclusion Occupational morbidity and industrial injuries are a consequence of unsatisfactory conditions and labor protection in enterprises.


2020 ◽  
Vol 4 ◽  
pp. 78-95
Author(s):  
A.R. Ivanova ◽  
◽  
E.N. Skriptunova ◽  
N.I. Komasko ◽  
A.A. Zavialova ◽  
...  

A review of literature on the impact of dust and sand storms on the air transport operation is presented. Observational data on dust storms at the aerodromes of European Russia for the period of 2001-2019 are analyzed. The seasonal variations in dust transport episodes at aerodromes and its relationship with visibility changes are discussed. The characteristics of dusty air masses and advection are given. It is concluded that the frequency of dust transfer episodes for the aerodromes under study has decreased over the past five years, except for Gumrak aerodrome (Volgograd). Keywords: dust storm, sand storm, aviation, visibility, seasonal variations, aerodrome оf European Russia


Author(s):  
E.N. Glavatskaya , O.V. Pribushenya , N.A. Venchikova

Two clinical cases of meconium peritonitis in the fetuses are presented. The diagnosis was made prenatally at 30+5 and 20+1 weeks of gestation. The main ultrasound signs were ascites, loop expansion and thickening of the intestinal wall, peritoneal calcifications, meconium pseudocysts. In one case, pregnancy was complicated by polyhydramnios. In both cases, the pregnancy ended in premature birth, followed by surgical treatment during the first days of life. A review of the literature on the topic are discussed the etiology, the spectrum and frequency of ultrasound signs suggesting this condition in the fetus, the effectiveness of prenatal diagnosis, the prognosis for the life and health of the newborn, as well as the impact of the quality and timeliness of the prenatal diagnosis on the management of pregnancy and timeliness of surgical care for the newborn.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
R. Shah ◽  
F. M. Ali ◽  
A. Y. Finlay ◽  
M. S. Salek

Abstract Background A person’s chronic health condition or disability can have a huge impact on the quality of life (QoL) of the whole family, but this important impact is often ignored. This literature review aims to understand the impact of patients' disease on family members across all medical specialities, and appraise existing generic and disease-specific family quality of life (QoL) measures. Methods The databases Medline, EMBASE, CINHAL, ASSIA, PsycINFO and Scopus were searched for original articles in English measuring the impact of health conditions on patients' family members/partner using a valid instrument. Results Of 114 articles screened, 86 met the inclusion criteria. They explored the impact of a relative's disease on 14,661 family members, mostly 'parents' or 'mothers', using 50 different instruments across 18 specialities including neurology, oncology and dermatology, in 33 countries including the USA, China and Australia. These studies revealed a huge impact of patients' illness on family members. An appraisal of family QoL instruments identified 48 instruments, 42 disease/speciality specific and six generic measures. Five of the six generics are aimed at carers of children, people with disability or restricted to chronic disease. The only generic instrument that measures the impact of any condition on family members across all specialities is the Family Reported Outcome Measure (FROM-16). Although most instruments demonstrated good reliability and validity, only 11 reported responsiveness and only one reported the minimal clinically important difference. Conclusions Family members' QoL is greatly impacted by a relative's condition. To support family members, there is a need for a generic tool that offers flexibility and brevity for use in clinical settings across all areas of medicine. FROM-16 could be the tool of choice, provided its robustness is demonstrated with further validation of its psychometric properties.


Author(s):  
Mateusz Iwo Dubaniowski ◽  
Hans Rudolf Heinimann

A system-of-systems (SoS) approach is often used for simulating disruptions to business and infrastructure system networks allowing for integration of several models into one simulation. However, the integration is frequently challenging as each system is designed individually with different characteristics, such as time granularity. Understanding the impact of time granularity on propagation of disruptions between businesses and infrastructure systems and finding the appropriate granularity for the SoS simulation remain as major challenges. To tackle these, we explore how time granularity, recovery time, and disruption size affect the propagation of disruptions between constituent systems of an SoS simulation. To address this issue, we developed a high level architecture (HLA) simulation of three networks and performed a series of simulation experiments. Our results revealed that time granularity and especially recovery time have huge impact on propagation of disruptions. Consequently, we developed a model for selecting an appropriate time granularity for an SoS simulation based on expected recovery time. Our simulation experiments show that time granularity should be less than 1.13 of expected recovery time. We identified some areas for future research centered around extending the experimental factors space.


2021 ◽  
Vol 11 (3) ◽  
pp. 1188
Author(s):  
William Hideki Ito ◽  
Talita Scussiato ◽  
Federico Vagnon ◽  
Anna Maria Ferrero ◽  
Maria Rita Migliazza ◽  
...  

Natural weathering is known as one of the key mechanisms causing degradation in building materials. Great efforts have been made to develop new materials and new processes for protecting those that already exist. Natural stones are an example of a natural material that has been extensively used for building construction since ancient times. In addition, they fit durability, aesthetic, and mechanical requirements. Thus, they still have great importance in the construction business nowadays. Though chemical interactions in natural stones, such as oxidation or hydrolyses, have been widely studied, in the last few decades, the physical weathering due to daily temperature variations has begun to be considered as a key mechanism of degradation and has been incorporated in international standards. This process is particularly important in calcitic marble slabs, where it can cause extensive damages to facades. Consequently, there are restrictive rules for the use of marble as an external coating material in many countries. In this paper, the thermal stresses induced by daily variations in temperature are calculated using geographic and meteorological information. The concept of sol-air temperature is used to estimate the temperatures of the hidden and exposed surfaces of a slab, and Fourier’s law and the theory of elasticity are used to calculate the temperature and stress distribution, respectively. The proposed methodology allows for a detailed reconstruction of the stress induced inside marble slabs using parameters commonly acquired in meteorological stations as input data. The developed methodology was validated by comparing in-situ measurements of the temperature of a building in Pescara (Central Italy). A good correlation between the theoretical and real temperatures was found; in particular, the peak tensile stresses inside the slabs were estimated at 75 kPa.


2021 ◽  
Vol 17 (1) ◽  
pp. 27-38
Author(s):  
Palak Thakur ◽  
Sharif Qamar

The paper intends to assess the impact of the odd–even scheme on the travel pattern of the daily commuters in Delhi. The objective of the paper is to assess the impact of the odd–even scheme on mode choice for daily work trips, shift in travel patterns – before, during, and post-implementation – of the odd–even scheme, and to understand people perception regarding the odd–even scheme. Based on the primary survey, the paper concludes that the odd–even scheme brought a significant impact in the travel pattern in terms of occupancy, travel cost, travel time, and modal shift, and statistically not so much on the air quality gain. It was observed that the scheme helped increase the occupancy rate in cars as well as ridership of buses and Delhi metro. The scheme had a huge impact on congestion, which was evident from both perception analysis and the change in travel time. The modal shift, with an improvement in public transport services and a reduction in car users, is one of the key successes of the scheme resulting in decrease in air pollution caused by private vehicles. To improve the outcome of the odd–even scheme on air pollution, two-wheelers should not be exempted going forward.


Religions ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 237
Author(s):  
Mehmet Ozalp ◽  
Mirela Ćufurović

Muslim youth have been under scrutiny over the last two decades from a radicalisation and countering violent extremism lens. This bias has largely carried itself to research conducted on Muslim youth in the West. This article undertakes a systematic review and analysis of literature conducted on Muslim youth in the West and in Australia in the last two decades since 11 September 2001. The body of literature in this field can be grouped under three main themes: (1) the impact of terrorism policies and discourse on Muslim youth and their disengaged identities, (2) the relationship between religion (Islam) and civic engagement of Muslim youth, and (3) Muslim youth as active citizens. An important conclusion of this review is that most of the research is dated. There have been significant changes in the development of youth as they quickly evolve and adapt. The systematic review of literature exposed a number of gaps in the research: the current literature ignores generic adolescent factors and external social factors other than Islam that also influence Muslim youth; studies that examine both online and traditional activism and volunteering space are needed to understand the dynamics of change and shift; research needs to focus on Muslim youth who were born and raised in Australia rather than focus only on migrant youth; the ways some Muslim youth use their unique sense of identity as Australian Muslims to become successful citizens engaged in positive action is not known; how Muslim youth use avenues other than their faith to express themselves in civic engagement and their commitment to society is underexplored; it is not known the degree to which bonding networks influence the identity formation and transformation of Muslim youth; there is no research done to examine how adult–youth partnership is managed in organisations that successfully integrate youth in their leadership; there is a need to include Australian Muslim youth individual accounts of their active citizenship; there is a need to understand the process of positive Muslim youth transformations as a complement to the current focus on the radicalisation process. Addressing these gaps will allow a more complete understanding of Muslim youth in the West and inform educational and social policies in a more effective manner.


2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110106
Author(s):  
Walid Alam ◽  
Youssef Bouferraa ◽  
Yolla Haibe ◽  
Deborah Mukherji ◽  
Ali Shamseddine

The Coronavirus (COVID-19) pandemic had a huge impact on all sectors around the world. In particular, the healthcare system has been subject to an enormous pressure that has surpassed its ability in many instances. Additionally, the pandemic has called for a review of our daily medical practices, including our approach to colorectal cancer management where treatment puts patients at high risk of virus exposure. Given their higher median age, patients are at an increased risk for severe symptoms and complications in cases of infection, especially in the setting of immunosuppression. Therefore, a review of the routine colorectal cancer practices is needed to minimize risk of exposure. Oncologists should weigh risk of exposure versus the patient’s oncologic benefits when approaching management. In addition, treatment protocols should be modified to minimize hospital visits and admissions while maintaining the same treatment efficacy. In this review, we will focus on challenges that colorectal cancer patients face during the pandemic, while highlighting the priority in each case. We will also discuss the evidence for potential modifications to existing treatment plans that could reduce infectious exposure without compromising care. Finally, we will discuss the impact of the socio-economic difficulties faced by Lebanese patients due to a poor economy toppled by an unexpected pandemic.


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