Search results for "PUMP"
showing 10 items of 471 documents
Pump currents generated by the purified Na+K+-ATPase from kidney on black lipid membranes.
1985
The transport activity of purified Na+K+-ATPase was investigated by measuring the electrical pump current induced on black lipid membranes. Discs containing purified Na+K+-ATPase from pig kidney were attached to planar lipid bilayers in a sandwich-like structure. After the addition of only microM concentrations of an inactive photolabile ATP derivative [P3-1-(2-nitro)phenylethyladenosine 5'-triphosphate, caged ATP] ATP was released after illumination with u.v.-light, which led to a transient current in the system. The transient photoresponse indicates that the discs and the underlying membrane are capacitatively coupled. Stationary pump currents were obtained after the addition of the H+, N…
Novel method and instruments for the optimal techno-economic sizing of borehole heat exchangers
2021
El test de respuesta térmica (TRT) es ampliamente utilizado como método estándar para caracterizar las propiedades térmicas del terreno adyacente a un intercambiador de calor enterrado (BHE). Los métodos tradicionales para interpretar los resultados aplican soluciones analíticas o numéricas asumiendo que el terreno es infinito, homogéneo e isotrópico. Sin embargo, en realidad el subsuelo presenta generalmente una estructura estratificada y heterogénea, y por lo tanto las propiedades térmicas pueden variar sustancialmente con la profundidad. En este sentido y con la intención de resolver las limitaciones del TRT estándar, la presente tesis doctoral se centra en el desarrollo de métodos e ins…
Novel Concept for Electro-Hydrostatic Actuators for Motion Control of Hydraulic Manipulators
2021
Self-contained hydraulic cylinders have gained popularity in the recent years but have not been implemented for high power articulated hydraulic manipulators. This paper presents a novel concept for an electro-hydrostatic actuator applicable to large hydraulic manipulators. The actuator is designed and analyzed to comply with requirements such as load holding, overload handling, and differential flow compensation. The system is analyzed during four quadrant operation to investigate energy efficiency and regenerative capabilities. Numerical simulation is carried out using path control and 2DOF anti-swing of a hydraulic crane as a load case to illustrate a real world scenario. A comparison wi…
On the impact of forgetting on learning machines
1995
People tend not to have perfect memories when it comes to learning, or to anything else for that matter. Most formal studies of learning, however, assume a perfect memory. Some approaches have restricted the number of items that could be retained. We introduce a complexity theoretic accounting of memory utilization by learning machines. In our new model, memory is measured in bits as a function of the size of the input. There is a hierarchy of learnability based on increasing memory allotment. The lower bound results are proved using an unusual combination of pumping and mutual recursion theorem arguments. For technical reasons, it was necessary to consider two types of memory : long and sh…
Simulating pump-probe photo-electron and absorption spectroscopy on the attosecond time-scale with time-dependent density-functional theory
2013
Molecular absorption and photoelectron spectra can be efficiently predicted with real-time time-dependent density functional theory. We show herein how these techniques can be easily extended to study time-resolved pump-probe experiments, in which a system response (absorption or electron emission) to a probe pulse is measured in an excited state. This simulation tool helps with the interpretation of fast-evolving attosecond time-resolved spectroscopic experiments, in which electronic motion must be followed at its natural timescale. We show how the extra degrees of freedom (pump-pulse duration, intensity, frequency, and time delay), which are absent in a conventional steady-state experimen…
The Multi-period Multi-trip Container Drayage Problem with Release and Due Dates
2021
Abstract The Container Drayage Problem (CDP) aims at routing a fleet of trucks, based at a common terminal, to serve customers while minimizing the total travel distance. Each trip starts from and ends at the terminal, and handles a subset of customers. Each customer requires either that a container is picked up or delivered. We introduce a more realistic variant, i.e., the Multi-trip Multi-period CDP with Release and Due Dates (MM-CDP-RDD), in which the planning horizon is composed of several periods (days). On each day, each truck may perform more than one trip respecting the Release and Due Dates (RDD) associated with customer services, corresponding to the first and the last day on whic…
Concomitant Use of Statins, Metformin, or Proton Pump Inhibitors in Patients with Advanced Renal Cell Carcinoma Treated with First-Line Combination T…
2022
Background Drug-drug interactions are a major concern in oncology and may potentially affect the outcome of patients with cancer. Objective In this study, we aimed to determine whether the concomitant use of statins, metformin, or proton pump inhibitors affects survival in patients with metastatic renal cell carcinoma treated with first-line combination therapies. Methods Medical records of patients with documented metastatic renal cell carcinoma between January 2016 and November 2021 were reviewed at 17 participating centers. This research was conducted in ten institutions, including both referral centers and local hospitals. Patients were assessed for overall survival, progression-free su…
A Hybrid Power Supply with Variable Speed Drive for Automatically Move Irrigation Equipment: Margin of Feasibility
2021
Center pivot irrigation systems are widely used in agriculture. Their water pumping systems are primary energy consumers. The use of photovoltaic power plants and variable speed drives of electric motors can reduce energy costs. The purpose of this study is to determine the feasibility of integrating variable speed drives and photovoltaic modules into water pumping systems. A novel architecture of a pumping system was suggested. Its features are no battery backup and the sale of electricity into the grid.
Performance analysis of photovoltaic powered dc motor — Propeller system
2015
The application of autonomous directly photovoltaic (PV) powered electro-mechanical has received increasing attention for different applications (e.g. PV water pumping, PV powered cooling of arid climate greenhouses, solar vehicles etc). The PV array output is a nonlinear and time-dependent power supply that varies with solar intensity and cell temperature, so the performance characteristics of the directly PV-powered DC motor — propeller system are very different than when powered by a constant DC voltage. The focus of this work is to do performance analysis of directly PV-powered DC motor — propeller system. Through performance evaluation, it has been observed that power transfer matching…
Design, modeling, and simulation of a photovoltaic water pumping system
2018
Electric pumps cannot be fed in those areas where they are not connected to the electric public distribution grid. In those areas, it is useful to feed electric pumps by means of the electricity generated from renewable energy sources plants. Among these, the Solar Water Pumping Systems feed electric pump thanks to the electricity generated by a photovoltaic plant. In this paper, a whole SWPS is fully designed, modelled, and simulated in Matlab environment. The proposed implementation is an useful tool for SWPS testing.