7,959 research outputs found
Effect of foot motion on the rate of increase in discomfort with increase in vibration magnitude during fore-aft whole-body vibration
No full textEffect of foot vibration on the location of most discomfort for seated persons during fore-and-aft whole-body vibration
No full textNumerical simulation of liquid sloshing phenomena in partially filled containers
No full textIn the simulation of the dynamic load excited by sloshing in a partially filled tank, appropriate boundary conditions need imposing to calculate the impact pressure. Traditionally, a thin artificial buffer zone is adopted near the tank ceiling and a linear combination of free surface dynamic and rigid wall boundary conditions are imposed inside the buffer zone. This investigation demonstrates that no special treatment is needed to describe the free surface, because a two-fluid approach based on a level set method is used to solve the RANS equations in both water and air regions and the interface is treated as a variation of the fluid properties. All the boundary conditions adopted are those usually accepted in solutions of Navier-Stokes or Euler equations. Sloshing in a rectangular tank excited by a horizontal harmonic motion is assessed numerically at different filling levels and excitation frequencies. The dependency of numerical solution on grid resolution, time step size and the interface thickness are investigated. Further, numerical tests are conducted for a rectangular tank with both 45° and 60° chamfered ceiling corners subject to a harmonic rolling motion. The comparison of computed results with experimental data show the developed numerical method is capable of the simulation of dynamic pressure loads exerted on the tank walls and ceiling excited by fluid sloshing
A general linear mathematical model of power flow analysis and control for integrated structure-control systems
No full textAbstract
Generalized integrated structure–control dynamical systems consisting of any number of active/passive controllers and three-dimensional rigid/flexible substructures are investigated. The developed mathematical model assessing the behaviour of these complex systems includes description of general boundary conditions, the interaction mechanisms between structures, power flows and control characteristics. Three active control strategies are examined. That is, multiple channel absolute/relative velocity feedback controllers, their hybrid combination and an existing passive control system to which the former control systems are attached in order to improve overall control efficiency. From the viewpoint of continuum mechanics, an analytical solution of this generalized structure–control system has been developed allowing predictions of the dynamic responses at any point on or in substructures of the coupled system. Absolute or relative dynamic response or receptance, transmissibility, mobility, transfer functions have been derived to evaluate complex dynamic interaction mechanisms through various transmission paths. The instantaneous and time-averaged power flow of energy input, transmission and dissipation or absorption within and between the source substructure, control subsystems and controlled substructure are presented. The general theory developed provides an integrated framework to solve various vibration isolation and control problems and provides a basis to develop a general algorithm that may allow the user to build arbitrarily complex linear control models using simple commands and inputs. The proposed approach is applied to a practical example to illustrate and validate the mathematical model as well as to assess control effectiveness and to provide important guidelines to assist vibration control designers
CONSUMER LOYALTY IN TERMS OF PRODUCT QUALITY, PRICE PERCEPTION, AND SERVICE QUALITY WEDDING DRESS MAKING TJ COLLECTION IN KLATEN
No full textThis research aims to determine consumer loyalty's influence on product quality, price perception, and quality of service at the wedding dress manufacturing company TJ Collection in Klaten. The methodology used in this study with quantitative methods is sampling as many as 100 respondents and using the purpose sampling technique. Data collection techniques used in this study using questionnaires. Analysis tools used with SPSS. The results of this study show that consumer loyalty is influenced both simultaneously and partially by product quality, price perception, and service quality.
Keywords: consumer loyalty, product quality, price perception, service qualit
An investigation of an active landing gear system to reduce aircraft vibrations caused by landing impacts and runway excitations
No full textA mathematical model is developed to control aircraft vibrations caused by runway excitation using an active landing gear system. Equations are derived to describe the integrated aircraft – active system. The nonlinear characteristics of the system are modelled and it is actively controlled using a Proportional Integral Derivative (PID) strategy. The performance of this system and its corresponding passive system are compared using numerical simulations. It is demonstrated that the impact loads and the vertical displacement of the aircraft’s centre of gravity caused by landing and runway excitations are greatly reduced using the active system, which result in improvements to the performance of the landing gear system, benefits the aircraft’s fatigue life, taxiing performance, crew / passenger comfort and reduces requirements on the unevenness of runways
Will biological agents supplant systemic glucocorticoids as the first-line treatment for thyroid-associated ophthalmopathy?
No full textIn this article, the two authors present their opposing points of view concerning the likelihood that glucocorticoids will be replaced by newly developed biological agents in the treatment of active, moderate-to-severe thyroid-associated ophthalmopathy (TAO). TAO is a vexing, disfiguring and potentially blinding autoimmune manifestation of thyroid autoimmunity. One author expresses the opinion that steroids are nonspecific, frequently fail to improve the disease and can cause sometimes serious side effects. He suggests that glucocorticoids should be replaced as soon as possible by more specific and safer drugs, once they become available. The most promising of these are biological agents. The other author argues that glucocorticoids are proven effective and are unlikely to be replaced by biologicals. He reasons that while they may not uniformly result in optimal benefit, they have been proven effective in many reports. He remains open minded about alternative therapies such as biologicals but remains skeptical that they will replace steroids as the first-line therapy for active, moderate-to-severe TAO without head-to-head comparative clinical trials demonstrating superiority. Despite these very different points of view, both authors are optimistic about the availability of improved medical therapies for TAO, either as single agents or in combination. Further, both agree that better treatment options are needed to improve the care of our patients with active moderate-to-severe TAO
BAURAN PEMASARAN PRODUK MARTABAK TJ (TUNA JAGUNG) RNFROZEN FOOD DI BANDA ACEH
No full textMartabak TJ (Tuna Jagung) adalah martabak yang dibuat dari ikan tuna dan jagung serta bahan lainnya yang balut dengan kulit lumpia. Usaha martabak TJ dipacu oleh banyaknya peminat makanan yang berbahan dasar ikan serta banyaknya peminat makanan cepat saji, dengan harga yang relatif murah. Pemasaran martabak TJ dilakukan secara online melalui WhatsApp dan Instagram dan juga secara offline. Cara ini lebih efektif serta efisien karena lebih praktis memilih target pasar yang potensial.Tujuan dari tugas akhir ini adalah untuk mengetahui bagaimana bauran pemasaran 4P (product, price, place dan promotion) dan STP (segmenting, targeting dan positioning) pada usaha martabak TJ. Pengumpulan data dilakukan melalui survei menggunakan kuesioner yang diisi oleh 34 responden. Penulis menyebarkan link google form yang berisi beberapa pertanyaan tentang produk martabak TJ melalui whatsApp kepada konsumen martabak TJ. Metode analisis yang digunakan adalah metode deskriftip.Berdasarkan hasil tugas akhir ini, usaha martabak TJ menerapkan empat bauran pemasaran 4P (product, price, place, dan promotion), Produk memiliki cita rasa yang khas dan rasa yang enak yang cocok dengan semua kalangan, harga yang ditawarkan terjangaku oleh semua kalangan, tempat produksi dan pemasaran strategis dan mudah didapatkan, promosi yang digunakan oleh produk martabak TJ melalui promosi secara langsung dan tidak langsung seperti menggunakan media sosial seperti Instagram dan whatsApp.Strategi pemasaran yang digunakan pada pengembangan usaha ini yaitu strategi pemasaran seperti segmenting, targeting dan positioning. Produk martabak TJ dipasarkan kepada semua kalangan tidak menentukan target usia, status, dan pola tingkah laku atau kebiasaan. Produk dipasarkan disekitar tempat produksi dan sekitarnya. Produk ini mudah dikenali dari namanya yaitu martabak TJ, nama tersebut diambill dari bahan dasar yang digunakan dalam pembuatan produk ini, yaitu Tuna Jagung. Produk martabak TJ dijual dengan harga Rp.12.000 per pack dengan berat 120 gram dengan isian 4 pcs. Lokasi produksi berada di daerah Banda Aceh, tepatnya di Kopelma Darussalam, Syiah Kuala
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