Ku & C Band solid state switch matrix for satellite payloads using LTCC multilayer substrate

This paper describes the design and development of Ku and C band solid state switch matrix for multimedia satellite payloads. The design, through the use of advanced packaging techniques, allows significant savings on mass and volume with respect to traditional electromechanical switches while guaranteeing a comparable reliability

A case of double cystic esophageal duplication in VACTERL syndrome: the first case report and a review of the literature

BackgroundAn esophageal duplication cyst (EDC) is a rare malformation resulting from the embryonic foregut. VACTERL syndrome is a genetic disorder affecting many systems of the human body. We report the first case of VACTERL syndrome associated to asymptomatic double EDC.Case reportA girl with anorectal malformation and rectovestibular fistula, kidney malformation, and various vertebral defects came to our attention at the time of birth. VACTERL disease was diagnosed. She underwent Peña anoplasty at 4 months of life without complications. MRI was conducted at the age of 2. It accidentally showed a double esophageal duplication (12 mm × 35 mm × 10 mm) at the D7–D9 level. We planned a thoracoscopy; previous intraoperative esophagogastroduodenoscopy showed an external compression of the native esophagus. Two duplicated esophageal lesions were removed. The patient made an uneventful recovery and was completely asymptomatic at long-term follow-up.ConclusionsVACTERL syndrome is still a not well-defined disease. Based on the current literature, this is the first case of a double esophageal duplication in a patient affected by VACTERL syndrome. According to us, the thoracoscopic approach of esophageal duplications can be followed by experts. Complete surgical excision is possible even if the cyst shares a common muscular wall with the esophagus. For this reason, we suggest to close the muscular wall by a simple interrupted suture

The woods around the ivory tower: A systematic review examining the value and relevance of school forests in the United States

Throughout the United States, many institutions of higher education own forested tracts, often called school forests, which they use for teaching, research, and demonstration purposes. These school forests provide a range of benefits to the communities in which they are located. However, because administration is often decoupled from research and teaching, those benefits might not always be evident to the individuals who make decisions about the management and use of school forests, which may undervalue their services and put these areas at risk for sale, development, or over-harvesting to generate revenue. To understand what messages are being conveyed about the value and relevance of school forests, we conducted a systematic literature review and qualitatively coded the resulting literature content using an ecosystem services framework. While school forests provide many important benefits to academic and local communities, we found that most of the existing literature omits discussions about cultural ecosystem services that people may receive from school forests. We discuss the implications of this omission and make recommendations for addressing it

An Efficient Induction Motor Vector Controller for Washing Machines Applications

This paper presents an efficient controller for washing machine applications employing an on-line energy optimizer. The control scheme is based on a standard rotor flux fieldo-rientation for three phase induction motors. The torque current command is given by the speed regulator whilst the flux current command is given by the energy optimiser. The proper level of flux is selected in order to minimise the motor input power for any speed/torque operating condition. The proposed system does not require any additional measurements with respect to a standard vector controller. Experimental investigations are presented based on a TMS320F240 DSP controller, an IGBT inverter and a four poles, 500 W induction motor for washing machine applications. The system performance and the efficiency improvements achieved by the proposed controller are presented and discussed

Sensorless Control of IPM Motors in the Low-Speed Range and at Stand-Still by HF-Injection and DFT Processing

In this paper, a sensorless controller for an interior permanent-magnet synchronous motor is presented based on well-known high-frequency signal injection techniques. The issue of the demodulation process is the key point of this paper. A novel approach based on discrete Fourier transform and nonconventional reference frame transformation is presented, allowing a simple and robust noncoherent demodulation, i.e., in which no information about the carrier phase is needed. In the classically adopted coherent approaches, in fact, uncertainty about carrier phase reflects in uncertainty in the demodulated signal amplitude, affecting observer gains and signal-to-noise ratio and definitively providing a degradation of the performance of the estimator. Analytical development of the sensorless algorithm, including the demodulation technique, is provided. A complete investigation by simulation is carried out aiming at showing the performance of the proposed method. Finally, experimental results are presented based on a prototype motor drive for city scooters. \ua9 2011 IEEE

Sensorless control of IPM motors in the low-speed range and at stand-still by HF-injection and DFT processing

In this paper a sensorless controller for an IPM synchronous motor is presented, based on well-known high-frequency signal injection techniques. The issue of the demodulation process is the key-point of the paper. A novel approach based on Discrete Fourier Transform (DFT) and non conventional reference frame transformation is presented allowing a simple and robust non-coherent demodulation, i.e. in which no information about the carrier phase is needed. In the classically adopted coherent approaches, in fact, uncertainty about carrier phase reflects in uncertainty in the demodulated signal amplitude, affecting observer gains and signal-to-noise ratio, definitively providing a degradation of the performance of the estimator. Analytical development of the sensorless algorithm including the demodulation technique is provided. A complete investigation by simulation is carried out aiming at showing the performance of the proposed method. Finally, experimental results are presented based on a prototype motor drive for city-scooters

One trocar assisted pyeloplasty (OTAP): initial experience and codification of a technique

BACKGROUND: The Anderson-Hynes pyeloplasty is still the gold standard for the surgical treatment of the ureteropelvic junction obstruction (UPJO) in children. To reduce the surgical invasivity, laparoscopic (RPSc) and retroperitoneoscopic (RPSc) pyeloplasty have been proposed but concerns have been expressed. In the RPSc approach, the small operative space and the technical difficulties have limited the application and diffusion of this techinique while in case of laparoscopy, a transperitoneal technique is used to treat a retroperitoneal disease. We report our initial experience with the "one trocar assisted pyeloplasty" (OTAP) in the treatment of UPJO in children. METHODS: From January 2005 to December 2006 sixteen children (13 males--3 females) from 2 to 18 months of age (mean age 5.6 months), with impaired monolateral renal function underwent surgical treatment for UPJO. In 11 cases the obstruction was on the left side and in one case a crossing vessel was found. The renal pelvis was anteriorly reached using a 10 mm operative telescope via a flank 12 mm incision. The UPJ was exteriorized and a dismembered pyeloplasty performed also for the crossing vessel. In two cases a 6 Fr uretero-pyelo-nephrostomy catheter was used. RESULTS: The patients were discharged after four days without complications. The cosmetic results are excellent. In one case, a small perianastomotic leakage was seen. The ultrasonographic follow-up demonstrated the spontaneous resolution of the leakage. The post operative US follow-up showed the reduction of the dilatation in all cases. DISCUSSION: This is an initial experience and a longer follow-up is needed. However, in our opinion the OTAP could be considered as a safe and feasible alternative to the laparoscopic or retroperitoneoscopic pyeloplasty, especially in very small children and also in presence of crossing vessels

THORACOSCOPIC REMOVAL OF RESIDUAL BURNED ESO- PHAGUS

Introduction The most frequent cause of esophagectomy in chil- dren is the presence of strictures related to the ingestion of corrosive agents. When dilatations of burned esopha- gus are not feasible due to high risk of rupture or when those are unsuccessful, surgical treatment is mandatory. Operative strategy is controversial regarding esophageal substitution and timing of surgery, while the need for eso- phagectomy to avoid risk of cancer is internationally re- cognised.We report one case of thoracoscopic esophagec- tomy as a delayed intervention after open esophagoco- lonplasty in a child with a burned esophagus. Materials and methods A two years old child with a severe esophageal steno- sis for accidental ingestion of liquid caustic soda, reached our institution from Mali. A retrosternal isoperistaltic esofagocolonplasty was realised without removing the esophagus. 11 months later the child underwent a com- plete right thoracoscopic esophagectomy. The patient was positioned in a left lateral decubitus and five trocars were used. A 5 mm for the telescope was positioned at the seventh intercostal space on the midaxillary line. Two 5 mm operative trocars were placed at the fifth and nineth intercostal space posteriorly to the optic, while two 3 mm trocars were positioned anteriorly to the optic to retract the lung. A single lung ventilation was used. The azigos vein was sectioned and the residual esophagus dissected with a monopolar hook and his lower tract was separated from the stomach with a stapler. The defunc- tioned esophagus was removed from a 5 mm port. Results The toracid drain was removed after 24 h and no respi- ratory problem was seen. The patient was discharged after 11 days and came back to his country in a good condition. Discussion Open esophagectomy can be associated with high morbidity and delayed return to routine activities. Tho- racoscopic esophagectomy have been proposed both for benign and malignant pathology in adults, while in chil- dren the esperience is still poor. In case of caustic burned esophagus, the intense fibrosis and adherences can lead to accidental lesions of the mediastinal structures. Lapa- roscopic magnification can allow a secure controll of the situation. In our opinion thoracoscopic esophagectomy, in expert hands, can be performed avoiding the risk of long term morbidity of scoliosis, shoulder muscle girdle weakness, and chest wall deformities