Speed Sensorless Control Based on Initial Rotor Position Detection for EESM

Electrically excited synchronous motor (EESM) is widely used in many large equipment drives because of its strong overload capacity, high efficiency, and adjustable power factor. The research and development of a high-performance EESM control system can realize the high combination of energy-saving speed regulation and green environmental protection and has a high social effect and economic value. In this paper, the signal injection method is used to obtain the initial rotor position information of EESM. Sliding Fourier transform is used to improve the initial position angle detection method based on the rotor signal injection method, and the improved method is compared with the traditional voltage integration method. Rotor high-frequency signal injection method was used to detect the rotor position information of the motor during operation, and the influence of the damping winding on the rotor signal injection method was analyzed. On the premise that the damping winding had no influence on the method, a method of obtaining the rotor position information of EESM without a speed sensor was designed. Finally, the speed sensorless regulation system using the initial rotor position detection method is simulated, which verifies the accuracy of the proposed speed sensorless control scheme.

Sequential injection method for bi-parametric determination of iron and manganese in soil leachates

Sequential injection method for bi-parametric determination of Fe and Mn in soil leachates to assess the impact of micronutrients supplementation.

The use of intrarenal injection of sodium pentobarbital for euthanasia in cats

OBJECTIVE To determine whether intrarenal injection of sodium pentobarbital is a viable method for euthanasia in anesthetized client-owned cats and assess potential factors associated with time to cardiopulmonary arrest (TCPA) for such treated cats. ANIMALS 131 client-owned cats. PROCEDURES In this retrospective study, client-owned cats presented for euthanasia between March 1, 2009, and January 15, 2010, were evaluated by veterinarians to determine suitability of intrarenal injection versus other methods of euthanasia. Cats included were anesthetized and then received 6 mL of sodium pentobarbital (390 mg/mL) by intrarenal injection. Results for TCPA were compared for cats grouped on the basis of variables of interest. RESULTS 131 cats were included, of which 74 (79%) had a TCPA < 1 minute and 28 (21%) had a TCPA between 1.5 and 8 minutes after intrarenal injection. Most (124/131 [95%]) cats had no observable reaction to the intrarenal injection other than cardiopulmonary arrest. Median TCPA was longer for cats without (1 min; 25/131 [19%]) versus with (0 min; 106/131 [81%]) palpable kidney swelling upon injection. CLINICAL RELEVANCE The effects of intrarenal injection of sodium pentobarbital in cats of the present study were similar to those typically observed with IV administration of euthanasia solution. When this intrarenal injection method is used, cardiopulmonary arrest with few agonal reactions can be expected to occur quickly in most patients. The intrarenal injection method is suited for euthanasia of anesthetized cats with easily located kidneys when IV access may be difficult.

The Intrinsic Electrochemical Behavior of Layered Cu2WSe4 Nanoparticles

Nanoplates of Cu2WSe4 (~50 nm) were synthesized via a hot-injection method by one-pot selenation of WCl6 and Cu(acac)2. This synthetic route provided another path towards deciphering the intrinsic electrochemical properties of Cu2MSe4 (M = Mo or W), where their nanoparticles were previously synthesized via a metathesis route. Cation-dependent cathodic events and surface activation anodic events were identified by cyclic voltammetry in acetonitrile.