scholarly journals Impact of Wind on the Movement of the Load Carried by Rotary Crane

2019 ◽  
Vol 9 (18) ◽  
pp. 3842 ◽  
Author(s):  
Cekus ◽  
Gnatowska ◽  
Kwiatoń
Keyword(s):  
Dynamic Models ◽  
Wind Pressure ◽  
Full Description ◽  
Mechanical Equipment ◽  
Work Cycle ◽  
Rotary Crane ◽  
Mobile Crane ◽  
Load Movement ◽  
External Forces ◽  
The Impact

This paper considers the coupled kinematic and dynamic models of a mobile crane. A full description of boom and load movement has been provided as a response of the system to the influence of kinematic forces. The linear system model was treated as rigid, and the carried load as a nondeformed static body. To describe the position of said load, Bryant angles were used. The dynamic model includes the impact of external forces (wind pressure) while load carrying and positioning. Algorithm and calculation software were developed to enable dynamic phenomena analysis during both a work cycle and free movement of said load. The initial problem was solved by means of the ode45 calculation procedure in the Matlab software based on the Runge–Kutta 4th Order Method. The work presents exemplary results of load movement simulation with respect to various wind velocities, selected on the basis of guidelines from Poland’s standards regarding safe operation of mechanical equipment.

Monetary policy and the effect of the transfer of oil prices to inflation

2020 ◽  
pp. 41-50
Author(s):  
Ph. S. Kartaev ◽  
I. D. Medvedev
Keyword(s):  
Monetary Policy ◽  
Inflation Targeting ◽  
Dynamic Models ◽  
Oil Prices ◽  
Oil Price ◽  
Oil Price Shocks ◽  
Negative Effects ◽  
Price Shocks ◽  
Policy Regime ◽  
The Impact

The paper examines the impact of oil price shocks on inflation, as well as the impact of the choice of the monetary policy regime on the strength of this influence. We used dynamic models on panel data for the countries of the world for the period from 2000 to 2017. It is shown that mainly the impact of changes in oil prices on inflation is carried out through the channel of exchange rate. The paper demonstrates the influence of the transition to inflation targeting on the nature of the relationship between oil price shocks and inflation. This effect is asymmetrical: during periods of rising oil prices, inflation targeting reduces the effect of the transfer of oil prices, limiting negative effects of shock. During periods of decline in oil prices, this monetary policy regime, in contrast, contributes to a stronger transfer, helping to reduce inflation.

scholarly journals Model of thermal buoyancy in cavity-ventilated roof constructions

2021 ◽  
pp. 174425912098418
Author(s):  
Toivo Säwén ◽  
Martina Stockhaus ◽  
Carl-Eric Hagentoft ◽  
Nora Schjøth Bunkholt ◽  
Paula Wahlgren
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Numerical Study ◽  
Air Flow ◽  
Wind Pressure ◽  
Air Flow Rate ◽  
Test Set ◽  
Air Cavity ◽  
Thermal Buoyancy ◽  
The Impact

Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.

scholarly journals Online Reviews and Product Sales: The Role of Review Visibility

2021 ◽  
Vol 16 (4) ◽  
pp. 638-669
Author(s):  
Miriam Alzate ◽  
Marta Arce-Urriza ◽  
Javier Cebollada
Keyword(s):  
Decision Making ◽  
Dynamic Models ◽  
Generalized Method Of Moments ◽  
Online Reviews ◽  
Consumer Decision Making ◽  
Product Sales ◽  
The Impact ◽  
The Relationship ◽  
The Empirical Analysis

When studying the impact of online reviews on product sales, previous scholars have usually assumed that every review for a product has the same probability of being viewed by consumers. However, decision-making and information processing theories underline that the accessibility of information plays a role in consumer decision-making. We incorporate the notion of review visibility to study the relationship between online reviews and product sales, which is proxied by sales rank information, studying three different cases: (1) when every online review is assumed to have the same probability of being viewed; (2) when we assume that consumers sort online reviews by the most helpful mechanism; and (3) when we assume that consumers sort online reviews by the most recent mechanism. Review non-textual and textual variables are analyzed. The empirical analysis is conducted using a panel of 119 cosmetic products over a period of nine weeks. Using the system generalized method of moments (system GMM) method for dynamic models of panel data, our findings reveal that review variables influence product sales, but the magnitude, and even the direction of the effect, vary amongst visibility cases. Overall, the characteristics of the most helpful reviews have a higher impact on sales.

Family Service Agencies: Responding to Change in a Conservative Decade

1992 ◽  
Vol 73 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Diane Elias Alperin
Keyword(s):  
Social Services ◽  
Environmental Changes ◽  
Nationwide Survey ◽  
Social Service Agencies ◽  
Family Service ◽  
Family Service Agencies ◽  
Responding To Change ◽  
External Forces ◽  
The Impact ◽  
Service Agencies

During the 1980s much of the concern in social services has focused on the impact of external forces on agencies—namely the increase in the problems of the American family with a simultaneous decrease in commitment from the U.S. government for funding and services. A nationwide survey of Family Service America, Inc., member agencies was undertaken in an attempt to assess partially the impact of these environmental changes on voluntary social service agencies. The data indicate that the increased needs of the community took precedence over the decline in public sector support. Response to a conservative environment led to interorganizational changes, which allowed for program expansion in an attempt to meet the increased demand for human services.

scholarly journals KAZAKHSTAN-CHINESE RELATIONS AND CHALLENGE OF FOREIGN FORCES

2020 ◽  
Vol 66 (3) ◽  
Author(s):  
Kanat Kakar ◽  
Keyword(s):  
United States ◽  
Central Asia ◽  
International Organizations ◽  
The United States ◽  
Rich Country ◽  
One Belt One Road ◽  
Road Project ◽  
The One ◽  
External Forces ◽  
The Impact

In 2013, China's Silk Road Initiative, the One Belt One Road project, was first mentioned in Kazakhstan and has been widely discussed by major countries and international organizations. Kazakhstan's participation in this project, a resource-rich country in Central Asia, has attracted world attention, and the impact of external forces on Central Asia will have its own impact on the implementation of this project. The interests of countries such as Russia and the United States in Central Asia and the views of international organizations are important factors in the implementation of this project. This article examines the relations between China and Kazakhstan in the framework of the "One Belt - One Road" initiative and the competition of external forces influencing it, their views on the project, their interests, the project and competing projects, and highlights important international organizations and agreements. and the toothed conclusion is pronounced.

scholarly journals Structural Assessment of the Hull Response of an FPSO Unit to Dropped Objects: A Case Study

2019 ◽  
Vol 26 (4) ◽  
pp. 39-46 ◽  
Author(s):  
Ozgur Ozguc
Keyword(s):  
Structural Damage ◽  
Local Buckling ◽  
Structural Response ◽  
Offshore Structures ◽  
Mechanical Equipment ◽  
Structural Members ◽  
Impact Area ◽  
Explicit Dynamic ◽  
The Impact

Abstract Offshore structures are exposed to the risk of damage caused by various types of extreme and accidental events, such as fire, explosion, collision, and dropped objects. These events cause structural damage in the impact area, including yielding of materials, local buckling, and in some cases local failure and penetration. The structural response of an FPSO hull subjected to events involving dropped objects is investigated in this study, and non-linear finite element analyses are carried out using an explicit dynamic code written LS-DYNA software. The scenarios involving dropped objects are based on the impact from the fall of a container and rigid mechanical equipment. Impact analyses of the dropped objects demonstrated that even though some structural members were permanently deformed by drop loads, no failure took place in accordance with the plastic strain criteria, as per NORSOK standards. The findings and insights derived from the present study may be informative in the safe design of floating offshore structures.

scholarly journals Assessing the impact of widespread respirator use in curtailing COVID-19 transmission in the USA

2021 ◽  
Vol 8 (9) ◽  
pp. 210699
Author(s):  
Calistus N. Ngonghala ◽  
James R. Knitter ◽  
Lucas Marinacci ◽  
Matthew H. Bonds ◽  
Abba B. Gumel
Keyword(s):  
Dynamic Models ◽  
Effective Control ◽  
Natural Immunity ◽  
Third Wave ◽  
Respiratory Protection ◽  
The Third ◽  
Surgical Masks ◽  
The Usa ◽  
Baseline Levels ◽  
The Impact

Dynamic models are used to assess the impact of three types of face masks (cloth masks, surgical/procedure masks and respirators) in controlling the COVID-19 pandemic in the USA. We showed that the pandemic would have failed to establish in the USA if a nationwide mask mandate, based on using respirators with moderately high compliance, had been implemented during the first two months of the pandemic. The other mask types would fail to prevent the pandemic from becoming established. When mask usage compliance is low to moderate, respirators are far more effective in reducing disease burden. Using data from the third wave, we showed that the epidemic could be eliminated in the USA if at least 40% of the population consistently wore respirators in public. Surgical masks can also lead to elimination, but requires compliance of at least 55%. Daily COVID-19 mortality could be eliminated in the USA by June or July 2021 if 95% of the population opted for either respirators or surgical masks from the beginning of the third wave. We showed that the prospect of effective control or elimination of the pandemic using mask-based strategy is greatly enhanced if combined with other non-pharmaceutical interventions (NPIs) that significantly reduce the baseline community transmission. By slightly modifying the model to include the effect of a vaccine against COVID-19 and waning vaccine-derived and natural immunity, this study shows that the waning of such immunity could trigger multiple new waves of the pandemic in the USA. The number, severity and duration of the projected waves depend on the quality of mask type used and the level of increase in the baseline levels of other NPIs used in the community during the onset of the third wave of the pandemic in the USA. Specifically, no severe fourth or subsequent wave of the pandemic will be recorded in the USA if surgical masks or respirators are used, particularly if the mask use strategy is combined with an increase in the baseline levels of other NPIs. This study further emphasizes the role of human behaviour towards masking on COVID-19 burden, and highlights the urgent need to maintain a healthy stockpile of highly effective respiratory protection, particularly respirators, to be made available to the general public in times of future outbreaks or pandemics of respiratory diseases that inflict severe public health and socio-economic burden on the population.

scholarly journals The Simulation of Sloped Bank Effect Influence on Container Ship Trajectory

2021 ◽  
Vol 9 (11) ◽  
pp. 1283
Author(s):  
Mate Baric ◽  
Robert Mohovic ◽  
Djani Mohovic ◽  
Vinko Pavic
Keyword(s):  
Traffic Flow ◽  
Significant Influence ◽  
Suez Canal ◽  
Container Ship ◽  
Design Standards ◽  
Bank Effect ◽  
Flow Through ◽  
External Forces ◽  
The Impact ◽  
Vessel Speed

The latest container vessel grounding in the Suez Canal, which occurred on 23 March 2021 (the Ever Given), raised many questions regarding the safety of navigation. The sudden concern about safety is due to fears that traffic flow through the Suez Canal could be blocked for longer periods of time. Besides external forces imposed by wind, in this case bank effect had a significant influence on the ship’s grounding. Bank effect occurs due to restricted water flow caused by narrow waterways. Many fairway design standards consider sloped banks such as those of the Suez Canal as unsubstantial in bank-effect forces. This paper analyses the impact of sloped banks on container ship trajectory and proposes minimal distances that may decrease bank-effect forces in order to reduce the risk of vessel grounding and increase the safety of navigation. However, this type of accident has happened before and may occur again due to a small sailing distance from the bank in cases where vessel speed is increased.

The Uses and Abuses of Time

Dead Ringers ◽  
2011 ◽  
Author(s):  
Shehzad Nadeem
Keyword(s):  
Work Hours ◽  
Ordinary Life ◽  
Global Outsourcing ◽  
Network Time ◽  
Corporate Globalization ◽  
Work Cycle ◽  
Transnational Companies ◽  
The Impact ◽  
Mental And Physical Health ◽  
Night Shifts

This chapter examines how transnational companies make use of what it calls time arbitrage—the exploitation of time discrepancies between geographical labor markets to make a profit. The extension of work hours through global outsourcing raises the possibility of a 24-hour work cycle. This means long hours for offshore Indian workers. The other option is the direct adoption of Western timings in offshore offices. This translates into permanent night shifts for workers as spatial and temporal disorientation are neatly combined. The chapter considers the impact of offshore workers' long, busy, and odd hours on family and friends as well as mental and physical health. It highlights the tension between the network time of corporate globalization and the prosaic rhythms of ordinary life. It shows that time arbitrage has resulted in long work hours, an intense work pace, and temporal displacement among Indian offshore workers.

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