Effects of temperature and humidity on acute myocardial infarction hospitalization in a super-aging society

Weather conditions affect the incidence of acute myocardial infarction (AMI). However, little is known on the association of weather temperature and humidity with AMI hospitalizations in a super-aging society. This study sought to examine this association. We included 87,911 consecutive patients with AMI admitted to Japanese acute-care hospitals between April 1, 2012 and March 31, 2015. The primary outcome was the number of AMI hospitalizations per day. Multilevel mixed-effects linear regression models were used to estimate the association of the average temperature and humidity, 1 day before hospital admission, with AMI hospitalizations, after adjusting for weather, hospital, and patient demographics.Lower temperature and humidity were associated with an increased number of AMI hospitalizations (coefficient − 0.500 [− 0.524 to − 0.474] per °C change, p < 0.001 and coefficient − 0.012 [− 0.023 to − 0.001] per % change, p = 0.039, respectively). The effects of temperature and humidity on AMI hospitalization did not differ by age and sex (all interaction p > 0.05), but differed by season. However, higher temperatures in spring (coefficient 0.089 [0.025 to 0.152] per °C change, p = 0.010) and higher humidity in autumn (coefficient 0.144 [0.121 to 0.166] per % change, p < 0.001) were risk factors for AMI hospitalization. Increased average temperatures and humidity, 1 day before hospitalization, are associated with a decreased number of AMI hospitalizations.

STABILITAS PELAT ORTHOTROPIK AKIBAT BEBAN LEDAKAN FRIEDLANDER DAN BEBAN IN-PLANE

Slab behavior due to static and dynamic load needs to be considered when designing a slab. Friedlander is one of the examples of dynamic loads. This dynamic load can give different responses on slab. This research discusses about orthotropic plate on Pasternak foundation with fixed boundary condition and in-plane and Friedlander load. Three phases on Friedlander load are positive phase, negative phase, and free vibration phase. This research is conducted to find out critical buckling load due to variation of Pasternak foundation parameters which is spring coefficient and shear coefficient. The system responses are deflection and bending moment due to variation of Pasternak foundation parameter, critical loading, position of loads, depth of soil, and duration of positive phase. Analysis is carried out using Modified Bolotin Method to obtain natural frequencies and mode shape of the system. Result of this research are displayed in graphics and tables. Based on the results, the maximum limit of the critical compressive load is 77% of the critical load used. The increasing of soil coefficient, the greater the deflection that occurs. The position of the load that is close to the center of the span will make the deflection even greater. The deflection that occurs is greater when the depth of the soil increases and the duration of the blast load is getting longer. The greater the thickness of the plate, the smaller the deflection. Keywords : Modified Bolotin Method, Friedlander blast load, plate deflection, critical load, Pasternak FoundationAbstrakPerilaku pelat akibat adanya beban statik dan beban dinamik perlu menjadi pertimbangan pada saat mendesain pelat. Salah satu contoh beban dinamik adalah beban ledakan setempat (Friedlander). Beban dinamik dapat memberikan respon yang beragam pada pelat. Penelitian ini membahas mengenai pelat orthotropik di atas pondasi Pasternak dengan kondisi jepit dengan beban in-plane dan beban ledakan setempat (Friedlander). Beban ledakan setempat (Friedlander) dianalisis dalam tiga fase yaitu fase positif, fase negatif, dan fase getaran bebas. Penelitian dilakukan untuk mengetahui beban tekuk kritis akibat variasi koefisien pondasi Pasternak yaitu koefisien pegas dan koefisien geser. Respons sistem yang diamati adalah lendutan dan momen yang dihasilkan akibat adanya variasi terhadap parameter pondasi Pasternak, besaran beban kritis, posisi beban, kedalaman tanah, dan durasi fase positif beban. Analisis dilakukan dengan Modified Bolotin Method untuk mendapatkan frekuensi alami dan ragam getar yang terjadi. Hasil analisis akan dibandingkan dalam bentuk grafik dan tabel. Berdasarkan hasil penelitian, batas maksimum beban tekan kritis adalah 77% dari beban kritis yang digunakan. Koefisien tanah yang semakin besar akan membuat lendutan yang terjadi semakin besar. Posisi beban yang mendekati tengah bentang akan membuat lendutan semakin besar. Lendutan yang terjadi semakin besar apabila kedalaman tanah semakin meningkat dan durasi beban ledakan yang semakin lama. Apabila semakin besar tebal pelat maka lendutan yang terjadi semakin kecil.

Simulation of nano elastic polymer chain displacement under pressure gradient/electroosmotic flow with the target of less dispersion of transition

Since non-scattering transfer of polymer chain in nanochannel is one of the important issue in biology, in this research, the behavior study of a long polymer chain in the nanofluid in two modes of free motion and restricted motion (fixed two ends) under two different forces including constant force (pressure gradient (PG)) and variable force (electroosmotic force (EOF)) has been investigated using dissipative particle dynamics (DPD) method. Our aim is that displacement of polymer chain carries out with less dispersion. Initially, without the presence of polymer, the results have been validated in a nanochannel by analytical results for both cases (PG, EOF) with an error of less than 10%. Then, assuming 50 beads of polymer chain, the polymer chain motion in free motion and fixed two ends modes has been examined by different spring coefficients between beads and different forces including PG (0.01 DPD unite) and EOF (zeta potential = − 25 mV, electric field = 250 V/mm, kh parameter = 8). The results show that in free polymer motion-PG mode, by increasing 1.6 times of spring coefficient of the polymer, a 40% reduction in transition of polymer is achieved, which high dispersion of polymer chain is resulted for this mode. In the EOF, the spring coefficient has a slight effect on transferring of polymer and also, EOF moves the polymer chain with extremely low polymer chain scattering. Also, for fixed two ends-PG mode, a 36% reduction in displacement is achieved and in the same way, in EOF almost 39% declining in displacement is resulted by enhancing the spring coefficients. The results have developed to 25 and 100 beads which less dispersion of polymer chain transfer for free polymer chain-EOF is reported again for both circumstances and for restricted polymer chain state in two PG and EOF modes, less differences are reported for two cases. The results show that the EOF has the benefit of low dispersion for free polymer chain transfer, also, almost equal displacement for restricted polymer chain mode is observed for both cases.

Sliding Mode Control of Lateral Semi-Active Suspension of High-Speed Train

A control algorithm for lateral semi-active suspension based on sliding mode observer is proposed to solve lateral vibration of high-speed trains caused by railway surface excitation. Firstly, the multi-degree-of-freedom vehicle dynamics model of high-speed train is revised on the basis of variation in spring coefficient caused by long-time vibration in practical engineering; Secondly, the observer based on sliding mode variable structure is designed to obtain real-time estimation of unknown interference terms using the equivalent control principle of sliding mode variable structure, which can be further used to calculate the observed values of unknown interference terms; Finally, a control algorithm based on sliding mode observer is proposed. The algorithm inputs complex unknown interference observed values into the sliding mode controller (SMC) as feedback, thereby allowing the observed values to accurately track nonlinear unknown disturbance and weaken the vibration. Stimulation and experimental verification have proven the effectiveness and feasibility of the proposed method.

Longitudinal vibration compensation model of stepped-pipe strings in deep-sea mining

In this paper, the dynamic model of the rigid space stepped-pipe strings system is derived with Lagrangian method to represent the system dynamic behaviors which enriches the analysis method of longitudinal vibration of stepped-pipe strings. The stepped-pipe strings is constructed of pipes with different diameters and lengths, the physical properties of which mainly depends on the axial force and the depth of deep-sea mining. Based on lumped element method, the heave compensation system with dynamic vibration absorber is designed for longitudinal vibration suppression of the stepped-pipe strings. The analytical solution is obtained by modal analysis method when the mining ship is subjected to sea breeze excitation. The proposed method is easily implementable for rigid space stepped-pipe strings system with complex multi-degree-of-free deep-sea mining dynamic model. Furthermore, the optimal combination of mass ratio, spring coefficient and damping ratio is shown to have a better vibration suppression performance. Finally, numerical simulations on the stepped-pipe strings system with or without dynamic vibration absorbers are provided to demonstrate the effectiveness of the proposed method.

Effects of Spring and Damper Elements in Aircraft Landing Gear Dynamics

In this study a typical Aircraft Landing Gear with shock absorber was modeled a Mass-Spring-Damper System. Basic components of the system were explained. The equations of the model was presented. Aircraft Landing Gear was also modeled in Matlab/Simulink for a given set of aircraft parameters. A case study for an Aircraft Landing Gear was solved and results were presented. Results included the variation of spring (k1 and k2 ) and damping coefficient (b) in a given interval to show their effects on the impact force and displacement of landing gear as main outputs to consider. Effect of damping coefficient (b) on impact force was found to be highest (3.76%), spring coefficient (k1 ) effect is moderate (2.29%), and spring coefficient (k2 ) is lower (0.97%), for a change of ±10% of coefficients.

Dynamic Response and Analytical Approach on a Double Catalyst Muffler System Mounting on a Table

For preventing fatigue failures caused by the vibration stresses in a moving vehicle or an operating machine, it is important to clarify and predict dynamic response behaviors. Assuming a rigid installation, the vibration transmissibility of a double catalyst muffler system mounting on a table was examined through a vibration machine. Based on the measured data and by systematically taking vibration theories into consideration, a new prediction method of the vibration modes and parameters was proposed that takes account of vibration coupling and damping. A lumped vibration model with the eight-element and two mass points was set up, and the vibration response parameters were analyzed accurately from simultaneous equations of motion. In the vibration test, resonance peaks from the mounting table and muffler parts of two units were confirmed in three excitation drives. The first resonance peaks caused by the mounting table had lower frequency, but the vibration magnitudes from other parts at higher frequency were damped to a considerable degree. With examples where the mounting table was reinforced by a damping material bracket, and where the spring coefficient of the connecting pipe between the two units in the sample was changed, the resonance frequencies and transmissibilities were obtained by calculation using the analytical model, demonstrating the model’s general versatility as a prediction method.