scholarly journals Screens surrounding openings in floor slabs of public buildings

2021 ◽  
Vol 30 (1) ◽  
pp. 32-41
Author(s):  
V. I. Prisadkov ◽  
D. V. Ushakov ◽  
A. A. Abashkin ◽  
A. S. Zueva
Keyword(s):  
Selection Algorithm ◽  
Public Buildings ◽  
Evacuation Time ◽  
Fire Hazards ◽  
Second Stage ◽  
Floor Slabs ◽  
Protection Systems ◽  
Screen Height ◽  
Multi Level ◽  
Selection Of

Introduction. Screens often surround openings in the floor slabs of atrium buildings to prevent the spread of fire hazards to higher floors and to improve the efficiency of smoke ventilation systems. In this article, the co-authors assess the expediency of installing screens around openings in the floor slabs and identify the best screen height values. In this article, the co-authors perform a quantitative analysis of the ability of screens to prevent the propagation of hazardous fire factors, to identify general regularities typical for a multi-level space, and to develop recommendations for the installation of screens inside public buildings. The co-authors suggest that screen height should be a solution to the following tradeoff problem: the use of screens reduces acceptable evacuation time for the floor that has screens installed and rises the evacuation time for higher floors.Rational screen height selection algorithm. The co-authors propose the following algorithm for the two-stage selection of the rational screen height. At the first stage, the evacuation problem is resolved. As a result, evacuation completion time is determined for emergency exits. Further, acceptable evacuation time and the time needed to block emergency floor exits are identified for a particular type of a fire alarm system.At the second stage, the dynamics of hazardous fire factors in building rooms is assessed for various screen heights. As a result, the rational height of screens is established for the evacuation time to remain positive.Conclusions. Screen height values cannot be determined in advance. Each case requires an individual approach that entails the resolution of evacuation problems and the tracking of the dynamics of hazardous fire factors in buildings that have multi-height spaces. These ideas are in line with the concept of flexible regulation of fire protection systems designated for construction facilities.

Researching American Muslims: A Case Study of Surveillance and Racialized State Control

2021 ◽  
pp. 1-16
Author(s):  
Hajer Al-Faham
Keyword(s):  
United States ◽  
Science Research ◽  
The United States ◽  
State Control ◽  
Limited Data ◽  
American Muslims ◽  
State Repression ◽  
Second Stage ◽  
Selection Of

How does surveillance shape political science research in the United States? In comparative and international politics, there is a rich literature concerning the conduct of research amid conditions of conflict and state repression. As this literature locates “the field” in distant contexts “over there,” the United States continues to be saturated with various forms of state control. What this portends for American politics research has thus far been examined by a limited selection of scholars. Expanding on their insights, I situate “the field” in the United States and examine surveillance of American Muslims, an understudied case of racialized state control. Drawing on qualitative data from a case study of sixty-nine interviews with Arab and Black American Muslims, I argue that surveillance operated as a two-stage political mechanism that mapped onto research methodologically and substantively. In the first stage, surveillance reconfigured the researcher-researchee dynamic, hindered recruitment and access, and limited data-collection. In the second stage, surveillance colored the self-perceptions, political attitudes, and civic engagement of respondents, thereby indicating a political socialization unfolding among Muslims. The implications of this study suggest that researchers can mitigate against some, but not all, of the challenges presented by surveillance and concomitant forms of state control.

scholarly journals A Multiple and Multi-Level Substructure Method for the Dynamics of Complex Structures

2021 ◽  
Vol 11 (12) ◽  
pp. 5570
Author(s):  
Binbin Wang ◽  
Jingze Liu ◽  
Zhifu Cao ◽  
Dahai Zhang ◽  
Dong Jiang
Keyword(s):  
Structural Characteristics ◽  
Complex Structure ◽  
Complex Structures ◽  
System Matrix ◽  
Substructure Method ◽  
Residual Structure ◽  
The Matrix ◽  
Multi Level ◽  
Fixed Interface ◽  
Selection Of

Based on the fixed interface component mode synthesis, a multiple and multi-level substructure method for the modeling of complex structures is proposed in this paper. Firstly, the residual structure is selected according to the structural characteristics of the assembled complex structure. Secondly, according to the assembly relationship, the parts assembled with the residual structure are divided into a group of substructures, which are named the first-level substructure, the parts assembled with the first-level substructure are divided into a second-level substructure, and consequently the multi-level substructure model is established. Next, the substructures are dynamically condensed and assembled on the boundary of the residual structure. Finally, the substructure system matrix, which is replicated from the matrix of repeated physical geometry, is obtained by preserving the main modes and the constrained modes and the system matrix of the last level of the substructure is assembled to the upper level of the substructure, one level up, until it is assembled in the residual structure. In this paper, an assembly structure with three panels and a gear box is adopted to verify the method by simulation and a rotor is used to experimentally verify the method. The results show that the proposed multiple and multi-level substructure modeling method is not unique to the selection of residual structures, and different classification methods do not affect the calculation accuracy. The selection of 50% external nodes can further improve the analysis efficiency while ensuring the calculation accuracy.

A Target Selection Algorithm of Seeker Based on the Prior Information and SVM

2013 ◽  
Vol 734-737 ◽  
pp. 3071-3074
Author(s):  
Guo Dong Zhang ◽  
Zhong Liu
Keyword(s):  
Prior Information ◽  
Simulation Experiment ◽  
Target Selection ◽  
Support Vector ◽  
Selection Algorithm ◽  
Distribution Law ◽  
Surface Ship ◽  
False Target ◽  
Target Characteristics ◽  
Selection Of

Aiming at the phenomenon that the chaff and corner reflector released by surface ship can influence the selection of missile seeker, this paper proposed a multi-target selection method based on the prior information of false targets distribution and Support Vector Machine (SVM). By analyzing the false targets distribution law we obtain two classification principles, which are used to train the SVM studies the true and false target characteristics. The trained SVM is applied to the seeker in the target selection. This method has advantages of simple programming and high classification accuracy, and the simulation experiment in this paper confirms the correctness and effectiveness of this method.

scholarly journals Isolated individuals and groups show opposite preferences toward humidity

2018 ◽  
Author(s):  
Mariano Calvo Martín ◽  
Stamatios C. Nicolis ◽  
Isaac Planas-Sitjà ◽  
Jean-Christophe de Biseau ◽  
Jean-Louis Deneubourg
Keyword(s):  
Relative Humidity ◽  
Environmental Conditions ◽  
Group Level ◽  
Individual Level ◽  
Negative Effect ◽  
Multi Level ◽  
The Individual ◽  
Shed Light ◽  
Selection Of

AbstractCockroaches, like most social arthropods, are led to choose collectively among different alternative resting places. These decisions are modulated by different factors, such as environmental conditions (temperature, relative humidity) and sociality (groups size, nature of communications). The aim of this study is to establish the interplay between environmental conditions and the modulation of the interactions between individuals within a group leading to an inversion of preferences. We show that the preferences of isolated cockroaches and groups of 16 individuals, on the selection of the relative humidity of a shelter are inversed and shed light on the mechanisms involved. We suggest that the relative humidity has a multi-level influence on cockroaches, manifested as an attractant effect at the individual level and as a negative effect at the group level, modulating the interactions.

scholarly journals Coverage of the Sprayed Objects in the Aspect of the Coefficient of the Spray Surfaces

2018 ◽  
Vol 66 (1) ◽  
pp. 9-16
Author(s):  
Beata Cieniawska ◽  
Deta Łuczycka ◽  
Jan Červinka ◽  
Katarzyna Dereń
Keyword(s):  
Significant Influence ◽  
Strong Relationship ◽  
Morphological Features ◽  
Spray Characteristics ◽  
Mutual Relation ◽  
Second Stage ◽  
Laboratory Conditions ◽  
Two Stages ◽  
Selection Of

The aim of the study was to compare the degree of coverage of the sprayed objects with the selected nozzles in the aspect of the characteristics of the sprayed object, determined by the coefficient of the position of the sprayed surfaces. Studies were conducted in two stages, in laboratory conditions, in which the first step was to determine the characteristics of the sprayed objects, and in the second there were conducted the studies of the degree of coverage. Based on the analysis of the obtained results from the first stage it was stated that the studied plants were characterised by great differentiation of morphological features having a significant influence on the parameters of their spray characteristics. Important was the fact that the use of the coefficient of the spray surfaces Wpo, determining the mutual relation of particular sprayed surfaces facilitates the selection of the most appropriate nozzles and treatment parameters in relation with the morphological features of the plant. In the second stage, concerning the studies of the degree of the coverage it was stated that the selected nozzles differed strongly in the degree of coverage of vertical and horizontal objects. Differentiated coverage for particular nozzles had a strong relationship with the coefficient of spray surfaces, except that the dual‑spray nozzles covered the vertical surfaces better compared to the single‑spray nozzles, which covered the horizontal surfaces better.

scholarly journals Implementing the Refugee Resettlement Process: Diverging Objectives, Interdependencies and Power Relations

2021 ◽  
Vol 3 ◽  
Author(s):  
Hanna Schneider
Keyword(s):  
Selection Criteria ◽  
Comparative Case Study ◽  
Refugee Resettlement ◽  
Academic Literature ◽  
Research Gap ◽  
Multi Level ◽  
National Selection ◽  
Resettlement Programs ◽  
Selection Of

Refugee resettlement is implemented by many different national and international stakeholders who operate in different locations and on the basis of sometimes diverging objectives. The implementation of the resettlement process has thus been characterized as multi-level governance, with resettlement stakeholders coordinating and negotiating the selection of refugees for resettlement. Still, literature on the implementation of refugee resettlement has remained very limited and has mainly focused on one specific stakeholder or stage of the process. In addition, a common conceptualization of the different stages is currently missing in academic literature. To address this research gap, the article proposes a common terminology of all stages of the resettlement process. Highlighting the diversity of resettlement programs, the article relies on a comparative case study of the German resettlement and humanitarian admission programs from Jordan and Turkey. By drawing on the concept of multi-level governance, the article examines diverging objectives and interdependencies between resettlement stakeholders, such as UNHCR and resettlement countries. As a result, the article argues that the increasing emphasis on national selection criteria by resettlement countries, including Germany, puts resettlement countries even more in the center of decision-making authority–in contrast to a diffusion of power that characterizes multi-level governance.

scholarly journals Improving The Accuracy Of Selection Of Bird Radar Echoes Against A Background Of Atomized Clouds And Atmospheric Inhomogeneities

The Ring ◽  
2015 ◽  
Vol 37 (1) ◽  
pp. 3-18
Author(s):  
Leonid Dinevich
Keyword(s):  
Bird Migration ◽  
Meteorological Conditions ◽  
Flight Safety ◽  
Selection Algorithm ◽  
Radar Echoes ◽  
Military Aviation ◽  
Radar Echo ◽  
Reflected Signal ◽  
Selection Of ◽  
Polarization Fluctuation

Abstract The algorithm for bird radar echo selection was developed in Israel and has been successfully used for many years to monitor birds in periods of massive intercontinental migration in order to ensure flight safety in civil and military aviation. However, it has been found that under certain meteorological conditions the bird echo selection algorithm does not filter out false signals formed by atomized clouds and atmospheric inhomogeneities. Although the algorithm is designed to identify and sift false signals, some useful echoes from smaller birds are erroneously sifted as well. This paper presents some additional features of radar echoes reflected from atmospheric formations that can be taken into account to prevent the loss of useful bird echoes. These additional features are based on the use of polarization, fluctuation and Doppler characteristics of a reflected signal. By taking these features into account we can reduce the number of false signals and increase the accuracy of the bird echo selection algorithm. The paper presents methods for using radar echoes to identify species and sizes of birds, together with recommendations on using the data to ensure flight safety during periods of massive intercontinental bird migration.

Prevention of Historically Challenging Sustained Casing Pressure from Shallow Gas Through Re-Engineered Cement Design and Execution Methodology

2021 ◽  
Author(s):  
Farah Shakina Ezani ◽  
Myat Thuzar ◽  
Avinash Kishore Kumar ◽  
Chee Hen Lau
Keyword(s):  
Mitigation Measures ◽  
Design Parameters ◽  
Two Stage ◽  
Shallow Gas ◽  
Second Stage ◽  
The Past ◽  
Sustained Casing Pressure ◽  
Dual Stage ◽  
Casing Pressure ◽  
Selection Of

Abstract Sustained casing pressure (SCP) is a very costly event for any operator either at production phase or at the end of a well’s lifecycle. SCP is a result of incomplete hydraulic isolation across hydrocarbon bearing zone. In one of the gas fields in Malaysia, notoriously known for shallow gas hazard, drilled development wells which have reportedly been suffering SCP. In the past, various improvements in cement slurry design and placement methods were deployed in order to provide complete zonal isolation, especially at the shallow gas sand, yet SCP issue was encountered occasionally. In the current development campaign, different strategy to providing annulus sealing was adopted. This paper discusses proactive steps taken in the slurry design, fit together with the dual stage cementing approach, as a primary means of placing cement above the shallow hazard interval. During the design phase, essential key parameters that would lead to successful placement of cement in the annulus as well as unique slurry design that suits for two stage cementing methods were studied. Risk involved in first stage cementing is one of the most important steps that should be analyzed in detail and put mitigation measures in place to ensure the second stage cement job can be performed as planned. In addition to the slurry properties, such as fluid-loss value, gas-tightness, etc., thickening time and top of cement (TOC) of the lead slurry in the first stage cement job has become enormously critical in designing dual stage cementing job in order to assure cement ports in the stage collar are not covered with hard cement forcing the termination of second stage job prematurely. Besides cementing design, careful selection of the stage collar location and casing annulus packer in the string is also of significant importance in leading to successful two stage cement job. Two development wells with above approached has been delivered and no sustained casing pressure has been experienced. This proactive approach to use two stage cementing as primary plan has proven to successfully eliminate the risk of SCP, which was a frequent struggle in their sister wells drilled with primary cementing in the past in the same field. The risk analysis combined with careful considerations of critical cementing design parameters and selection of stage tool location have become a novel approach to combat against SCP in this gas field.

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