Active Control of Radiated Sound from Ducts

1992 ◽  
Vol 114 (3) ◽  
pp. 338-346 ◽  
Author(s):  
H. R. Hall ◽  
W. Brent Ferren ◽  
R. J. Bernhard
Keyword(s):  
Active Control ◽  
Primary Source ◽  
Secondary Source ◽  
Sound Power ◽  
Circular Duct ◽  
Secondary Sources ◽  
Single Location ◽  
Wide Range ◽  
Radiated Sound ◽  
And Control

The noise radiated by duct and pipe systems is modeled in the laboratory using a circular duct driven by a speaker at one end. Active control is achieved using a control speaker located adjacent to the open end of the duct. The objective of the investigation was to minimize the total sound power radiated by the duct and a single secondary source. However, the adaptive algorithm used by the controller for this investigation seeks to cancel the acoustic pressure only at a single location; that is, the location of the “error” microphone. Analytical studies predict that in order for the total sound power radiated by primary and secondary sources to be minimized, a single secondary source must radiate sound which is of approximately equal magnitude and opposite phase to the noise source and the error microphone must be placed somewhere in the plane of minimum pressure of an ideal acoustic dipole. These analytical results were verified in part, for the case of the secondary source facing the same direction as the primary source in the plane of the pipe outlet. Other cases were studied where the control speaker was located outside the plane of the duct outlet. The performance improved for these alternative orientations for a wide range of error microphone positions. Measured sound power with and without active control is shown for a range of frequencies and error microphone locations for three configurations of the duct and control source.

Corruption and control from the perspective of Islam

2020 ◽  
Vol 27 (2) ◽  
pp. 355-368
Author(s):  
Waled Younes E. Alazzabi ◽  
Hasri Mustafa ◽  
Ahmed Razman Abdul Latiff
Keyword(s):  
Primary Source ◽  
Point Of View ◽  
Self Control ◽  
Business Community ◽  
Influential Factor ◽  
Situational Factor ◽  
Secondary Source ◽  
Research Approach ◽  
Content Type ◽  
And Control

Purpose The purpose of this paper is to explore and provide insights into corruption and the control procedures from an Islamic perspective. Design/methodology/approach This paper adopts qualitative research approach using the holy Quran as a primary source and hadith of the Prophet Mohammed supported by the anecdotes of his companions as a secondary source and prior literature. Findings This paper offers an Islamic taxonomy of corruption that contains economic, managerial, financial, political, environmental, social and ethical corruption which is explicitly prohibited because of their consequence on societies. Islam establishes proactive, preventive, detecting and reactive procedures to control corruption and prescribes how to avoid its harmful consequences. The paper also reveals significant concepts in relation to individuals’ qualities that if taken care of, better chances to reduce corruption and better living conditions can be accomplished. Research limitations/implications The paper recommends means to the business community through providing managerial and practical procedures which can be used for limiting corruption effectively. However, this piece of work provides further explanations on corruption to improve our understanding on such a phenomenon and contributes to the literature from the perspective of Islam point of view. Originality/value The paper contributes to the debate on corruption, human, religion and control from an Islamic point of view, which is lacking. This paper finds evidence that loss of belief is a situational factor that leads to corrupt acts. Also, moral teaching in early ages is necessary for inner and self-control. Moral renovation is an influential factor that keeps individuals motivated and refrain from indulging into corrupt acts.

Passive and Active Control of the Radiated Sound Power from a Submarine Excited by Propeller Forces

2013 ◽  
Vol 57 (1) ◽  
pp. 59-71 ◽  
Author(s):  
Sascha Merz ◽  
Nicole Kessissoglou ◽  
Roger Kinns ◽  
Steffen Marburg
Keyword(s):  
Active Control ◽  
Sound Power ◽  
Radiated Sound ◽  
Radiated Sound Power

Active Control of Low-Frequency Sound Radiation From Vibrating Panel Using Planar Sound Sources

2001 ◽  
Vol 124 (1) ◽  
pp. 2-9 ◽  
Author(s):  
Kean Chen ◽  
Gary H. Koopmann
Keyword(s):  
Active Control ◽  
Near Field ◽  
Low Frequency ◽  
Sound Radiation ◽  
Sound Field ◽  
Sound Power ◽  
Frequency Range ◽  
Sound Sources ◽  
Frequency Sound ◽  
Secondary Sources

Active control of low frequency sound radiation using planar secondary sources is theoretically investigated in this paper. The primary sound field originates from a vibrating panel and the planar sources are modeled as simply supported rectangular panels in an infinite baffle. The sound power of the primary and secondary panels are calculated using a near field approach, and then a series of formulas are derived to obtain the optimum reduction in sound power based on minimization of the total radiate sound power. Finally, active reduction for a number of secondary panel arrangements is examined and it is concluded that when the modal distribution of the secondary panel does not coincide with that of the primary panel, one secondary panel is sufficient. Otherwise four secondary panels can guarantee considerable reduction in sound power over entire frequency range of interest.

scholarly journals AN OVERVIEW OF THE GENESIS, SOURCES, MANIFESTATIONS AND IMPACT OF SMALL ARMS AND LIGHT WEAPONS (SALW) IN NORTHERN NIGERIA

2020 ◽  
Vol 16 ◽  
pp. 195-218
Author(s):  
Babayo Sule ◽  
Ibrahim Kawuley Mikail ◽  
Muhammad Aminu Yahaya
Keyword(s):  
Political Institutions ◽  
Primary Source ◽  
Armed Conflicts ◽  
Secondary Source ◽  
Northern Nigeria ◽  
Small Arms ◽  
Intelligence Gathering ◽  
Secondary Sources ◽  
The North ◽  
Light Weapons

The protracted proliferation of Small Arms and Light Weapons (SALW) across the globe to Africa and specifically in Northern Nigeria has led to the explosion of social crises which culminated in insecurity situation in the region for more than a decade now. Armed conflicts emanated from the effects of the spread of SALW across the three geopolitical zones in the North which manifested in the Boko Haram insurgency in the Northeast, farmers-herders conflict in the Northcentral, armed banditry in the Northwest and ethnoreligious conflicts in addition to kidnappings in the region. The objective of this study is a critical and thorough investigation of the SALW in exacerbating armed conflicts in general in the Northern part of Nigeria. The problem is the scenario in which the armed conflicts are threatening to entirely destabilised the region and the manner in which the SALW are increasing despite the global efforts to contain their spread for security reasons. This research used a qualitative method of data collection and analysis. Both the primary and secondary sources were used. The primary source was the interview conducted with selected informants in the relevant area of study. The secondary source was the use of available literature on the subject matter of study and the discussions were made using thematic analytical interpretations. The research discovered that the rampant armed conflicts in Northern Nigeria is the reminiscent of the spread of SALW in the region which tantamount to the present critical security situation. Also, weak policy and political institutions contributed to the spread of SALW which means there is a need for a strong policy approach. The work recommends among other numerous suggestions that efforts should be intensified in intelligence gathering to detect the networking of the racketeers in the armed business and contain them appropriately as well as total blockage of the weapons’ route.

scholarly journals INFLUENCE OF THE ENVIRONMENT TO MAGGIE'S BEHAVIOR IN CRANE'S "MAGGIE: A GIRL OF THE STREET"

2021 ◽  
Vol 8 (1) ◽  
pp. 67-83
Author(s):  
Prawidya Y. Sigar ◽  
Olga Rorintulus ◽  
Imelda S. lolowang
Keyword(s):  
Qualitative Research ◽  
Primary Source ◽  
The Other ◽  
Secondary Source ◽  
Psychological Approach ◽  
Wrong Decision ◽  
Her Family ◽  
Secondary Sources ◽  
Love Relationship ◽  
Family Condition

The purpose of this research Is to reveal the infiuence of the environment to Maggie's behavior In Crane's “Maggie: A Giri of the Streets”. In conducting this research, the writer uses qualitative research In which the data are in the form of words rather than numbers. In analyzing data, the writer uses objective and psychological approach. The data collected in this research from two sources, primary and secondary sources. Primary source is Crane's “Maggie: A Girl of the Streets” and secondary source are the other books and data from internet that related to this research. The result of the research shows that Maggie has a miserable life that caused by her bad environment. It caused by her family condition, her Job, her neighborhood, her love relationship with Pete, and all the problems that she has to face in everyday of her life. She has to survive by anything ways in order to get a better life. But the conditions make her depressed. At the end of the story, Maggie chooses a wrong decision. She kilis her self.

The Analysis of Structural–Acoustic Coupling of an Irregular Enclosure Under the Excitation of Point Force and PVDF

2006 ◽  
Vol 129 (2) ◽  
pp. 202-208 ◽  
Author(s):  
Luo Chao ◽  
Rao Zhushi ◽  
Zhao Mei
Keyword(s):  
Polyvinylidene Fluoride ◽  
Sound Pressure ◽  
Primary Source ◽  
Point Force ◽  
Control Voltage ◽  
Secondary Source ◽  
Linear Distribution ◽  
Acoustic Coupling ◽  
Secondary Sources ◽  
Irregular Enclosure

The physical model of this paper is an irregular enclosure with double flexible plates. The primary source is the vibration of Plate A excited by a point force. The secondary source is the vibration of Plate B excited by a polyvinylidene fluoride (PVDF) actuator. First, the interaction of the PVDF actuator and a thin plate is analyzed and the distribution of strain and stress is gained. Based on the hypothesis of linear distribution of strain on two sections of the plate–film system, a formula is deduced to calculate the rate of the strain distribution. Then an experiment is proposed to test the sound pressure response in an irregular enclosure under the excitation of the PVDF actuator. Second, the theoretical formulas of the mode contributions of the two plates and the cavity are deduced. Then the formulas are converted into compact matrix equations. Thus the expression of sound response of one point in the enclosure is gained under the excitation of both the primary and the secondary sources. Based on these results, the sound pressure square is taken as the control aim function. At last the optimized curves of control voltage and control phase are achieved.

Spit guards, ethical policing and the need for an evidence-based approach

2018 ◽  
Vol 17 (3) ◽  
pp. 145-155 ◽  
Author(s):  
Peter Joyce ◽  
Wendy Laverick
Keyword(s):  
Police Officers ◽  
Grey Literature ◽  
Primary Source ◽  
Evidence Base ◽  
Evidence Based ◽  
Content Type ◽  
Secondary Sources ◽  
Advantages And Disadvantages ◽  
Wide Range ◽  
The Uk

Purpose The purpose of this paper is to assess the advantages and disadvantages of the use of spit guards by police forces in the UK and to make recommendations regarding an evidence-based approach to decisions related to the use of such equipment. Design/methodology/approach The paper is based upon an examination of a range of primary source material, secondary sources and grey literature. Findings Although the use of spit guards can be justified by factors that include the need to protect police officers from contracting serious infectious diseases, there are a number of problems that concern ethical policing and human rights. Concerns arise when spit guards are deployed against vulnerable individuals, are used offensively rather than defensively and when such equipment is deployed disproportionately against persons from Black and Minority Ethnic (BME) communities. Additionally, the image of the police may suffer if spit guards are accompanied by the use of excessive force which may be perceived as an abuse of police power. Practical implications The paper makes recommendations that a comprehensive evidence base is required to assist practitioners to make informed decisions regarding the deployment of spit guards. This evidence base should include the extent to which officers are spat at, medical evidence relating to spitting and the transmission of serious diseases, the views of the public concerning the deployment of spit guards and estimations as to whether such equipment will deter spitting by suspects of crime. Originality/value This paper provides an original academic contribution to the ongoing debate on the use of spit guards within policing. In particular, it brings together a wide range of material that relates to this topic and presents it as a coherent set of arguments located in a single source.

Active control of radiated sound power of a smart cylindrical shell based on radiation modes

2016 ◽  
Vol 114 ◽  
pp. 218-229 ◽  
Author(s):  
Ali Loghmani ◽  
Mohammad Danesh ◽  
Moon K. Kwak ◽  
Mehdi Keshmiri
Keyword(s):  
Cylindrical Shell ◽  
Active Control ◽  
Sound Power ◽  
Radiated Sound ◽  
Radiated Sound Power

scholarly journals Pemikiran Pendidikan Karakter Ibn Miskawaih (Telaah Filosofis)

2021 ◽  
Vol 1 (2) ◽  
pp. 232-247
Author(s):  
Ahmad Ihwani ◽  
Muhammad Noupal ◽  
Ari Sandi
Keyword(s):  
Character Education ◽  
Research Method ◽  
Primary Source ◽  
Data Interpretation ◽  
Primary Sources ◽  
Secondary Source ◽  
Philosophical Perspective ◽  
Secondary Sources ◽  
Library Research ◽  
Unit Processing

This study aims to analyze the concept of character education according to Ibn Miskawaih in a philosophical perspective with a focus on studies from the side of ontology, epistemology, and axiology. The research method used is the library research method. Sources of literature in this study consist of primary sources and secondary sources. The primary source of literature is the book of tahzib al-Akhlak, and the secondary source is references related to character education such as other books from Ibn Miskawaih's essays, journals, or proceedings. Data analysis begins with unit processing, categorization, and ends with data interpretation. The results showed that ontologically, character education is an effort to curb the three forces that exist in the human soul, so that all body activities become good and spontaneous without the need for prior consideration. Epistemologically, the character education method includes willpower, self-introspection, thariqun thabi'iyyah and opposition methods. Axiologically, character education boils down to the middle path (al-wasath), with main virtues such as al-hikmah (wisdom), al-'iffah (maintaining self-purity), as-Saja'ah (courage) and al-'adalah ( justice).

scholarly journals SURVEY FOR IDENTIFYING NON-ECO FRIENDLY PRINTING ACTIVITIES IN VARIOUS STAGES OF PRINTING WORKFLOW

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
N. Nandini ◽  
P. Hema ◽  
T. Miruthubashini ◽  
R. Viveka
Keyword(s):  
Sustainable Development ◽  
Carbon Footprint ◽  
Primary Source ◽  
Hazardous Substances ◽  
The Internet ◽  
Secondary Source ◽  
Printing Industry ◽  
Secondary Sources ◽  
Quantitative Identification ◽  
Printing Processes

This paper presents the study of parameters affecting the environment by the non-eco-friendly activities in the printing industry. The survey identifies the non-eco-friendly activities in various stages of printing processes and also identifies the VOC Emissions, Carbon footprint, and Wastage of Calendar & Newspaper Printing. Data were collected from both primary and secondary sources to fulfill the aim of the survey. The primary source of data was collected from the companies and the Secondary source of data was referred from a journal, published articles including the internet. The presented concept, Methodology, and results represent the contribution to sustainable development management. The paper analyzes the results of the quantitative identification of hazardous substances emitted in the printing industry. The main focus of this survey is to find out the non-ecofriendly activities and provide suggestions to make the environment better.

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