Vibration Isolation of a Compound Mounting System on an Elastic Floor

This paper describes a theoretical investigation of a vibration isolation of a mounting system which consists of three masses and two isolators on an elastic floor. The formulation of the transmissibility of the system is derived in a plain expression by the use of the receptance method. The following conclusions are obtained from the results of numerical calculations. The effect of the two mounting frequencies on the transmissibility is not changed, though the combination of them is exchanged. The loss factor of one of the isolators whose mounting frequency is lower than that of the other has a great effect on the first resonance. The loss factor of the other isolator has a great effect on the second resonance. When the top mass becomes lighter and the middle mass becomes heavier, the transmissibility is reduced above the second resonant frequency. The heavy bottom mass reduces the transmissibility above the third resonant frequency, but it makes the third resonance level rise

Vibration Damping of Beams and Plates by Mastic Deadner

Mastic deadner is widely used for the vibration reduction of thin plates and beams because of its easy treatment and low cost. In this paper, the damping capacity of the mastic deadner is investigated theoretically and experimentally. The vibrations of a beam and a plate covered with the mastic deadner under an external exciting force were analyzed by making use of an eigenfunction expansion method. Experiments with the beams and the plates were carried out, and the relation between the vibration amplitude and the thickness of the mastic deadner was investigated. From the theoretical and the experimental results, the following conclusions were obtained. The vibration amplitudes at the natural frequencies are remarkably decreased by the mastic deadner. The loss factor of the plate covered with the mastic deadner is proportional to the square of the ratio of the thickness of the mastic deadner to that of the basic beam and plate. The vibration amplitude at the natural frequency is inversely proportional to the square of the thickness ratio

Parametrically Excited Vibration with External Constant Load and Damping

The vibrations of gears can be expressed by differential equations of parametrically excited vibrations. In this paper, the stabilities of parametrically excited vibrations of the MeiBner and Mathieu types (the former expresses the torsional vibrations of spur gears and the latter expresses those of helical gears) and their vibrational characteristics in the stable region are theoretically investigated. Through this investigation, the effects of the helix angle and the damping factor on the vibrations of gears are made clear. The vibrations of helical gears are smaller than those of spur gears. And the vibrations of helical gears with a large helix angle are smaller than those with a small helix angle. When the damping factor ζ increases, the unstable region decreases, and the peak levels of vibrations decrease remarkably, although the amplitude at the other region does not decrease. When we drive a pair of gears at a speed whose meshing frequency is two times faster than the natural frequency of the gearing system, the gears with a small damping have a very large vibration, but the gears with a large damping rotate smoothly

Agile Testing: Improving the Process : Case Descom

The thesis was assigned by Descom, a marketing and technology company based in Jyväskylä. The aim of the thesis was to research the current state of testing inside the organization, and to improve on the existing processes and practices. The thesis was carried out as a design research (applied action research), because the focus was improving already existing processes inside a company. The theory base contains a wide range of subjects from agile development models, the testing process, and process improvement models to agile testing. Without a solid base of multiple aspects it would have been impossible to understand how the testing works as a process and how it could have been improved. As Descom uses agile development it was necessary to follow the same principles throughout the writing of the thesis and on results. As a result information was provided for the company about the current state of testing procedures at Descom and how to improve the testing and processes in the future. The documentation already existing for testing such as the test plan and test report were updated. New documents such as a process improvement plan based on Critical Testing Processes, test strategy and testing policy were also created. Figures of the testing process, and the processes for all test types in use were created to be used as a visual aid for understanding the testing as whole at Descom.Opinnäytetyön toimeksianto tuli Descomilta, joka on Jyväskylästä lähtöisin oleva markkinointi ja teknologia yritys. Työn tavoitteena oli tutkia testauksen tilaa organisaatiossa ja kehittää olemassa olevia prosesseja ja käytäntöjä. Tutkimusmenetelmäksi valikoitui kehittämistutkimus, koska painotus oli olemassa olevien prosessien kehityksessä yrityksen sisällä. Teoriapohjassa käsiteltiin monia aiheita ketterästä sovelluskehityksestä, testausprosessista ja prosessi kehityksestä aina ketterään testaukseen asti. Ilman kattavaa pohjaa monille osa-alueille, olisi ollut mahdotonta ymmärtää miten testaus toimii prosessina ja miten sitä pystyy kehittämään. Descom toimii ketterän sovelluskehityksen mukaisesti projekteissaan, joten oli tärkeää seurata samoja ketteriä periaatteita läpi opinnäytetyön kirjoittamisen ja tuloksissa. Tuloksena saatiin tietoa yritykselle, siitä miten testaus on toiminut Descomilla ja kuinka testausta ja prosesseja tulisi kehittää tulevaisuudessa. Myös aiemmin olemassa olleet testausdokumentit päivitettiin. Uusina dokumentteina laadittiin suunnitelma prosessikehitykseen, joka perustui Critical Testing Processes –malliin, testausstrategia ja testauspolitiikka. Prosessikuvaus tehtiin kaavioita käyttäen, joilla kuvattiin prosessi kokonaisuutena sekä käytettävät testaustasot

Dynamic absorber for ropeway gondola using Coriolis force

Wind-induced swinging of ropeway gondola can be reduced using dynamic absorbers. To maximize the performance of conventional dynamic absorbers, their location should be as high as possible. However, absorbers can not be installed at high positions due to interference issues with structures such as towers and stations. To address this problem, a new type of dynamic absorber that moves vertically is proposed. This absorber is composed of a mass supported by a spring. The mass moves in the radius direction (up and down) and it induces Coriolis force in the circumference direction to prevent the swing of gondola. If the natural frequency of the absorber is tuned to twice that of the gondola, the absorber moves spontaneously with a large amplitude due the resonance. This absorber is more effective when it is located at lower positions. The experiment with a small model and an actual gondola for 10 passengers were carried out and the results agreed well with the theoretical predictions

ニワトリ卵心拍数の長期計測

Taking advantage of acoustocardiogram(ACG), we measured the heart rate(HR) of chick embryos continuously from day 12 until hatching and then investigated the development of HR irregularities(HRI), HR variability(HRV), and the existence of a circadian rhythm in mean HR(MHR). HRI comprised transient bradycardia and tachycardia, which first developed on day 14 and 16 in most embryos, respectively. Transient bradycardia increased in frequency and magnitude with embryonic development and occurred over periods of up to 30min in some embryos. MHR was maximal on around days 14-15 and thereafter decreased to about 250-260bpm on days 16-18. Baseline HRV, which is an oscillation of the MHR baseline, occurred as HR decreased from days 15-16 and became predominant on days 17-18. The magnitude of the baseline oscillations reached up to 50bpm in some embryos and the period ranged between about 40-90min (ultradian rhythm). A circadian rhythm of MHR was not found in late chick embryos. On days 18-19, embryonic activities were augmented and then breathing movements began to occur, disturbing ACG signals and thus making it difficult to measure the HR. Instead, the development of breathing activities was recorded. Breathing frequency was irregular at first and then increased to a maximum of about 1.5Hz prior to hatching.特集 : 「動物の心拍リズム」国際シンポジウム発表論文選

Taste receptor genes and renal function

Dysgeusia is not only associated with zinc deficiency but also with certain drugs or diseases, including diabetes and renal failure. It often lowers the patient’s quality of life and hinders access to proper nutrition. The underlying mechanism is unclear and there is a lack of awareness among patients. Here, we focused on lingual taste receptor gene expression in diabetes and elucidated the relationship between taste receptor gene expression and renal function. Forty-seven patients with diabetes and 10 healthy subjects (control group) were enrolled. Lingual foliate papillae were scraped and the derived cDNA was quantified by real-time polymerase chain reaction. Dysgeusia was assessed using SALSAVE®. All statistical analyses were performed using JMP® software 13. The expression of T1R1 and T1R2 was significantly upregulated in type 2 diabetes patients as compared with that in healthy subjects (P < 0.01) but did not change in type 1 diabetes patients. T1R3 expression positively correlated and Scnn1 expression negatively correlated with estimated glomerular filtration rate, suggesting that altered taste receptor gene expression could reflect impaired renal function. Thus, alterations in T1R3 and Scnn1 expression in diabetes correlated with renal function. Taste receptor gene expression dysregulation could indicate dysgeusia associated with impaired renal function in patients with diabetes

Up-Titration Strategy After DPP-4 Inhibitor-Based Oral Therapy for Type 2 Diabetes : A Randomized Controlled Trial Shifting to a Single-Dose GLP-1 Enhancer Versus Adding a Variable Basal Insulin Algorithm

Introduction: It is unclear whether adding basal insulin or enhancing incretin signaling with a glucagon-like peptide-1 receptor agonist (GLP-1RA) is more effective as an up-titration strategy after dipeptidyl peptidase-4 inhibitor (DPP-4i)-based oral antidiabetic drug (OAD) therapy. GLP-1RAs can be injected without dose adjustment, unlike basal insulin. Our objective was to examine the efficacy of changing patients inadequately controlled with oral DPP-4i-based OAD therapy to injectable GLP-1RA and discontinuing the DPP4i versus adding basal insulin glargine (IGlar) with the continuation of the oral DPP4i. Methods: Sixty patients with type 2 diabetes (T2DM) and glycated hemoglobin (HbA1c) between 7.0% and 10.0% on DPP-4i-based OAD therapy were randomized to either adding IGlar and remaining on the DPP-4i or liraglutide and discontinuing the DPP-4i for 24 weeks. Patients in the IGlar group started with 0.1 unit/kg and were titrated according to the algorithm. In the liraglutide group, the DPP-4i was replaced with liraglutide 0.9 mg/day, the maximum dose in Japan. We evaluated HbA1c, glycated albumin (GA), and anthropometrics. Results: HbA1c was significantly lower at week 24 (− 1.0 ± 0.9% in the IGlar group and − 0.6 ± 0.8% in the liraglutide group), but the difference between groups was not significant. Changes in GA were similar (− 2.9 ± 3.2% vs. − 2.6 ± 3.2%) in both groups. Body weight (BW) was significantly lower only in the liraglutide group (+ 0.5 ± 2.6 kg vs. − 2.2 ± 2.0 kg). The rate of minor hypoglycemic episodes was similar for both groups. Conclusion: For poorly controlled T2DM on DPP-4i-based OAD therapy, switching to single-dose liraglutide to enhance incretin signaling is as effective as dose-titrated basal IGlar, but significant BW reduction was only seen in the liraglutide group. These results suggest that enhancing incretin signaling with a single-dose injectable GLP-1 RA might be an alternative to dose-titrated basal insulin therapy in patients with T2DM poorly controlled with DPP-4i-based OAD therapy. These findings should be confirmed in a longer and larger trial

Usefulness of continuous blood glucose monitoring and control for patients undergoing liver transplantation

Background : The purpose of this study was to evaluate the usefulness of the closed-loop system (STG-22 ; Nikkiso, Tokyo, Japan), a type of artificial endocrine pancreas for the continuous monitoring and control of intraoperative blood glucose in patients undergoing liver transplantation. Methods : Sixteen patients undergoing livingdonor liver transplantation were enrolled in this study. Glucose levels were controlled with either a manual injection of insulin based on a commonly used sliding scale (manual insulin group, n=8) or a programmed infusion of insulin determined by the control algorithm of the artificial endocrine pancreas (programmed insulin group, n=8). The target glucose level range was set at 80-150 mg/dl. Results : The mean and SD of blood glucose concentration during surgery (Glu-Ave and Glu-SD, respectively) for the programmed insulin group were lower than for the manual insulin group. The coefficient of variability (Glu-CV=Glu-SD×100 /Glu-Ave) for the programmed insulin group was also lower than for the manual insulin group (20.1±4.9% vs. 26.9±6.1% ; mean±SD). No hypoglycemia was detected in either group. Conclusion : The STG-22 closed-loop system is effective for maintaining strict blood glucose control during liver transplantation with minimal variability in blood glucose concentration