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En este artículo se presenta un estudio empírico con profesores que enseñan ciencias naturales a nivel Bachillerato. Actualmente muchos profesores mantienen una imagen deformada de lo que es la ciencia y la tecnología. Algunos la conciben como un conocimiento acabado e infalible, otros como una actividad a-histórica y a-problemática o bien hay quienes la conciben como un quehacer elitista y descontextualizado.El propósito de este estudio es conocer cuáles son las preconcepciones sobre la ciencia y la tecnología, vigentes en los profesores de los bachilleratos de las 4 ciudades con mayor población del Estado de Guanajuato en México y con ello contribuir a mejorar la enseñanza de la ciencias y la tecnología.

A fundamental challenge in digital and sampled-data control arises when the controlled plant is subjected to fast disturbances with, however, a slow or limited sensor measurement. Such intrinsic difficulties are commonly encountered in many novel applications such as advanced and additive manufacturing, human-machine interaction, etc. This paper introduces a discrete-time regulation scheme for exact sampled-data rejection of disturbances beyond Nyquist frequency. By using a model-based multirate predictor and a forward-model disturbance observer, we show that the intersample disturbances can be fully attenuated despite the limitations in sampling and sensing. In addition, sharing the main properties of all-stabilizing control, the proposed control scheme offers several advantages in stability assurance and lucid design intuitions.

ABSTRAKLatar belakang: CTS merupakan penyakit yang sering dijumpai pada pekerja industri dalam setiap kasus penyakit akibat kerja di beberapa negara. Terdapat beberapa faktor yang dapat mempengaruhi angka kejadian CTS, salah satunya yaitu masa kerjaTujuan penelitian: Mengetahui hubungan masa kerja terhadap kejadian CTS pada pekerja pemetik daun teh.Metode penelitian: Analitik observasional dengan pendekatan Cross Sectional. Teknik pengambilan sampel menggunakan metode consecutive sampling dan didapatkan sampel sebanyak 85 pekerja.Hasil penelitian dan Diskusi: Angka kejadian CTS pada pekerja pemetik daun teh adalah 56 ( 65,9%), kejadian CTS meningkat setelah umur 40 tahun dan kejadian CTS tertinggi pada umur 50-59 tahun (30,6%), kejadian CTS meningkat setelah masa kerja 30 tahun dan kejadian CTS tertinggi terjadi pada masa kerja 30-39 tahun (31,8%). Korelasi antara masa kerja dengan kejadian CTS menunjukan nilai korelasi positif (0,263) dengan nilai signifikansi 0,015 (<0,05),yang artinya semakin lama masa kerja maka angka kejadian CTS semakin besar.Kesimpulan: Semakin lama masa kerja semakin tinggi resiko terjadinya CTS Kata kunci: Masa kerja, pekerja pemetik daun teh, CTS.

Abstract Horizontal wells are a proven and well acknowledged technology to enhance well productivity through an increase in reservoir contact compared to that of a vertical well under the same conditions. In the last three decades, a considerable effort has been directed to study flow around horizontal wells by many investigators. These studies have mainly focused on proposing practical tools (in the form of skin factor) for long-term well productivity estimation. The skin factor proposed can be applied in an equivalent (one dimensional radial) open-hole system replicating the flow around the actual complex three dimensional (3-D) flow geometry of the Horizontal well. However, all these studies concentrate on single-phase Darcy flow conditions. In gas condensate reservoirs, in addition to the three dimensional (3-D) nature of flow geometry, the flow behavior is further complicated by the phase change and the variation of relative permeability (kr) due to the coupling (increase in kr by an increase in velocity or decrease in IFT) and inertia (a decrease in kr by an increase in velocity) effects. Therefore, simulating such a complex 3-D flow using numerical commercial simulators requires a three dimensional fine grid compositional approach, which is very impractical, cumbersome and sometimes trigger convergence problems due to numerical instability. In fact, the introduction of a quick and reliable tool for long term productivity calculation is much needed in such systems. This work is aimed at the development of a practical, general, and easy-to-use method for defining an effective wellbore radius of an equivalent open-hole system, replicating flow around the 3-D Horizontal well in gas condensate reservoirs. Accordingly, a 3-D compositional finite element based in-house simulator was developed to accurately model gas and gas condensate flow around horizontal wells. A large data bank was generated, covering the impact of a wide range of pertinent geometric and flow parameters on the well performance. Then a general approach is proposed for estimation of an effective wellbore radius of an equivalent open-hole radial 1-D system replicating flow around the 3-D Horizontal well system. The effective wellbore radius varies with fluid properties, velocity, IFT, reservoir and wellbore conditions. The results of the proposed formulation, which benefits from suitable dimensionless numbers, has been tested against the simulator results not used in its development confirming the integrity of the approach. Also, the proposed formulation is applicable for both single-phase non-Darcy and two-phase gas condensate flow systems. With this approach, no numerical simulation is needed and instead a simple excel spread-sheet can predict the horizontal well performance, significantly facilitating engineering and management decisions relating to the application of horizontal well technologies.

One of us once worked in a place where a system administrator saw some *.log files in several directories and decided that since they were just log files, they could be deleted:

Microsoft Windows has always been a favorite platform for many people and organizations—for personal and business applications including Oracle Database. A sizable number of production databases, estimated at about 25 percent by Oracle Corporation, run on Windows. Needless to say, where there is a production Oracle Database, there is a need to protect it, and there is a place for RMAN. That's the purpose of this chapter: to help you put the power of RMAN to the most effective use on the Windows platform.

This chapter presents a methodical strategic technology engineering planning (STEP) approach, to effectively cope with the design complexity in service-oriented architecture and manage the strategic planning of solution development of information systems. This holistic model comprises four modules: Want-Is-Target (WIT) model, Transition and Alignment Grid (TAG), Comprehensive Architecting Process (CAP), and Joint Analysis & Roadmapping (JAR). The characteristics and features of the constituent elements in the STEP model are articulated in great detail. The WIT model defines three stages of architecture states – current, target, and end state. TAG specifies two dimensions for architecture planning, namely current-to-future state transformation and IT-to-Business alignment. CAP presents an overarching method for step-by-step engineering and design in system architecture and portfolio optimization. JAR comprises the best-of-breed strategic analysis techniques, accompanied by a hybrid method with strategy-driven and initiative-driven planning streams. Applying the framework in planning and future trends are also discussed in the context. This overarching framework provides a comprehensive multi-disciplinary approach to conducting strategic and tactical technology planning for both near-term needs and long-term goals.

Solutions architecting method (SAM) is defined as a methodical approach to dealing with the architecture complexity of enterprise information systems in IT solution designs. This comprehensive method consists of eight interconnected modules: framework for e-business architecture and technology, prescriptive artineering procedure, technology architecture planning, architecture stack and perspectives, rapid architecting process, architecture readiness maturity, generic application platform, and Tao of IT development & engineering. Collectively, these modules form a holistic discipline guiding the process of developing architected solutions in an enterprise computing environment. Several unconventional concepts and thinking styles are introduced in this overarching structure. This systematic method has been customized and adapted to be extensively applied in one form or another to develop various IT solutions across a broad range of industrial sectors. Reference solutions are presented and articulated to illustrate the exemplary implementations of some key elements in SAM. Best practice and lessons learned as well as future trends are discussed in the context.

Abstract A case history of an attempted CT intervention in 43' of water through a wellhead leaning at a 45 degree angle is presented. A major concern for this intervention was the integrity of the intervention stack between the leaning wellhead and the CT injector located on a lift boat. The stack design, testing and stack performance during the job execution are presented.