Integration of optical polymer pillars chip I/O interconnections with Si MSM photodetectors

We demonstrate the process integration and characterization of mechanically compliant optical polymer pillar chip I/O interconnections with Si metal-semiconductor-metal photodetectors (MSM-PDs). Polymer pillar waveguides with various cross-sectional geometry, size, and aspect ratio are fabricated on the active area of Ti-Si-Ti MSM-PDs. Some of the key performance metrics of the MSM-PDs before and after the process integration are reported. It is shown that the dark current of passivated Ti-Si-Ti PDs does not degrade as a result of the processing required to fabricate the polymer pillar I/O interconnections. In addition, the pillar integration does not degrade the responsivity as well as the normalized photo-to-dark current ratio of the MSM-PDs.     

Properties of blended cements with thermally activated kaolin

Kaolin, one of the materials of major importance for the ceramic and paper industry, is also used in the construction industry as a raw material for the production of white cement clinker and, in the form of metakaolin, as an artificial pozzolanic additive for concrete. Metakaolin is a vital component of high-performance and architectural concrete; however, its application in regular concrete is very limited due to relatively high production costs. This report evaluates the performance of a low-cost metakaolin-based additive called thermally activated kaolin (TAK), in cement. Due to its pozzolanic properties and the densification of cement matrix, the application of TAK provides a 15% improvement of the compressive strength. It was shown that TAK of optimal quality can be manufactured by the thermal treatment of raw kaolin with 74% of kaolinite at 750 °C without the intermediate beneficiation stage. The application of a developed approach can significantly reduce production expenditures and make the application of such an additive feasible even in regular-grade cement and concrete.     

Broadband and compact 2-D photonic crystal reflectors with controllable polarization dependence

Two-dimensional (2-D) compact photonic crystal reflectors on suspended InP membranes were studied under normal incidence. We report the first experimental demonstration of 2-D broadband reflectors (experimental stopband superior to 200 nm, theoretical stopband of 350 nm). They are based on the coupling of free space waves with two slow Bloch modes of the crystal. Moreover, they present a very strong sensitivity of the polarization dependence, when modifying their geometry. A compact (50/spl times/50 /spl mu/m/sup 2/) demonstrator was realized and characterized, behaving either as a broadband reflector or as a broadband transmitter, depending on the polarization of the incident wave. Experimental results are in good agreement with numerical simulations.     

Housing development and policy change: what has changed in Turkey in the last decade in the owner-occupied and rented sectors?

Since 2002, The Justice and Development Party has been governing in Turkey. From their first period to the current, major changes have been observed in the Turkish housing system, regarding both owner occupied and rented sectors. First one is the introduction of Mortgage Law in 2007. As already a home-owner society with a 64.16 % share in urban areas (2003), home ownership ratios can be argued to increase in coming periods. Second modification in owner occupied sector was significant policy change in Housing Development Administration (HDA) of Turkey. With a “housing mobilization” project, almost 500,000 new dwellings were built by HDA all over the country in 10 years. This has been a record in HDA’s history. Remarkable changes occurred in the rented sector as well. Originally, Turkey has been characterized with absence of public renting and considerable proportion of private rented stock especially in the big cities. Governments did not develop social rented housing and pro-owner laws have been followed. Renters could face eviction under certain situations determined by the Law on Property Rents, however these were subject to misuse by homeowners. As a third major change, a new Code of Obligations was introduced superseding Law on Property Rents. In this paper, recent changes in both rented and owner occupied sectors of the Turkish housing system are analyzed with reference to mortgage law, HDA’s new policies and changes in private renting legislation. In doing so, several key figures like buildings produced, inflation rate and physical attributes of private renting are provided.     

Integrated thermal-fluidic I/O interconnects for an on-chip microchannel heat sink

Power dissipation in microprocessors will reach a level that necessitates chip-level liquid cooling in the near future. An on-chip microfluidic heat sink can reduce the thermal interfaces between an IC chip and the convective cooling medium. Through wafer-level processing, integrated thermal-fluidic I/O interconnects enable on-chip microfluidic heat sinks with ultrasmall form factor at low-cost. This letter describes wafer-level integration of microchannels at the wafer back-side with through-wafer fluidic paths and thermal-fluidic input/output interconnection for future generation gigascale integrated chips.     

Aspects of 5-alpha reductase deficiency, a review

Two forms of 5 alpha-reductase deficiency have been described and two genes have been cloned. In view of the psychoendocrinological complexity of the primary form, the early diagnosis preferably in infancy, is crucial. Rearing up those who are assigned as females to the male gender identity could minimize the risk of gender identity and role disorders when puberty is reached.     

Reliable decentralized stabilization of linear systems

Reliable stabilization of linear time-invariant multi-input/multi-output plants is considered using a two-channel decentralized controller configuration. Necessary and sufficient conditions are obtained for existence of reliable controllers that maintain stability under the possible failure of either one of the two controllers. All decentralized controllers that achieve reliable stabilization are characterized     

Geothermal applications in Turkey

Geothermal energy is mostly utilised in direct applications in Turkey. The equivalent of 61,000 residences are currently heated by geothermal fluids. A total of 665 MW_t is utilised for space heating of residential, public and private property, and 565,000 m² of greenhouses. Geothermal fluids are also used in 195 spas (327 MW_t), bringing the total direct use capacity to 992 MW_t. ORME Geothermal Inc. has completed the engineering design of a geothermal district heating system that serves the equivalent of nearly 300,000 residences. A total of 170 geothermal fields have been explored so far in Turkey. At Kizildere a single-flash power plant with 20.4 MW_e installed capacity is integrated with a factory producing liquid CO₂ and dry-ice. A binary cycle power plant with an installed capacity of 25 MW_e will be constructed shortly at Aydin/Germencik. The proven geothermal heat capacity, according to data from existing geothermal wells and natural discharges, is 3132 MW_t (I. Akkus, MTA General Directorate, oral communication, January 2003).     

Interface-related reliability challenges in 3-D interconnect systems with through-silicon vias

During service, through-silicon vias (TSVs) in vertically stacked-die microelectronic packages are subjected to both thermo-mechanical cycling as well as electromigration. The disparate properties of Cu-filled TSVs and the Si chip induce substantial residual stresses in both components, as well as at the interface. These stresses may drive interfacial sliding with the interface serving as a rapid diffusion path, resulting in significant interfacial strain incompatibilities. In addition, by acting as short-circuit paths for diffusion, the interfaces may carry significant electromigration fluxes, further exacerbating interfacial sliding. The results of recent experiments and modeling are presented to illustrate these effects, and related reliability issues are discussed.