A comprehensive life cycle costs analysis of in-place recycling and conventional pavement construction and maintenance practices

Recent studies based on Life Cycle Assessment (LCA) have highlighted the potential of in-place recycling techniques to enhance the sustainability of agency pavement management decisions for asphalt pavements. However, a solution which an LCA finds environmentally advantageous might not be preferred over another which is technically equivalent, if it is not economically competitive. In this context, it is necessary to evaluate the economic costs of such alternatives taking into account the perspective of the main stakeholders who interact with a pavement system throughout its life cycle. This paper presents a comprehensive pavement life cycle costs (LCC) model that accounts for the different categories of costs incurred by highway agencies and road users in every phase of the pavement life cycle. The results of the application of the pavement LCC model to a specific highway rehabilitation project in the state of Virginia showed that in-place recycling practices are beneficial for both highway agencies and road users.     

Control of multiple bandgap shifts in InGaAs-AlInGaAsmultiple-quantum-well material using different thicknesses of PECVD SiO2 protection layers

A useful development of the sputtered SiO₂ intermixing technique is reported, which uses a single stage of sputtered SiO₂ deposition and annealing to achieve precise tuning of the bandgap energy in the InGaAs-AlInGaAs material system. The blue shift of photoluminescence spectra can be varied in the range of 0-160 nm. Bandgap-tuned lasers were integrated on a single chip using this technique to assess the post-processed material characteristics and demonstrate its application in optoelectronic integration     

Increase in external quantum efficiency of encapsulated silicon solar cells from a luminescent down‐shifting layer

This paper reports the external quantum efficiency (EQE) of encapsulated screen‐printed crystalline silicon solar cells, where the encapsulation includes a layer of luminescent down‐shifting (LDS) molecules. At wavelengths less than 400 nm, the inclusion of the LDS molecules increases the EQE from near zero to, at most, 40%. The increase in EQE corresponds to a rise in short‐circuit current density of 0·37 ± 0·13 mA/cm² under the AM1‐5g spectrum. Copyright © 2008 John Wiley & Sons, Ltd.     

Transition metal doped cadmium manganese telluride: A new material for tunable mid-infrared lasing

Relatively new materials for mid-infrared tunable lasing using chromium-doped Cd_1-xMn_xTe and cobalt-doped Cd_1-xMn_xTe have been developed. Previously, ZnS and ZnSe were used as host materials for chromium to produce mid-infrared (MIR) lasing. Compared to these materials, large diameter CdMnTe is easier to grow (using the Bridgman technique) and can be made more homogeneous. Moreover, the ternary nature of Cd_1-xMn_xTe offers the unique opportunity to optimize the optical properties of the material through variation of chemical composition and lattice parameter. Using Cd_0.55Mn_0.45Te:Cr, we have demonstrated room temperature lasing from 2.1 to 3.0 m, and we have demonstrated quasi-continuous wave (cw) lasing. To our knowledge, the observed tuning range (∼840 nm) of Cr²⁺:Cd_0.55Mn_0.45Te is the largest ever reported from a transition metal ion laser. Furthermore, this is the first time that a room temperature quasi-cw laser operating at 3 m has been demonstrated using this type of material. Also, preliminary work on Cd_0.55Mn_0.45Te:Co indicates its potential for tunable mid-infrared lasing around 3600 nm at cryogenic temperatures. Results from inductively coupled plasma mass spectrometry (ICP-MS), which determine the concentration of dopant that has been incorporated in to the host lattice, will be reported, as will the materials characterization and lasing results. The processing issues for optimizing the laser performance in these material systems will also be discussed.     

Cognitive–behavioral therapy versus usual clinical care for youth depression: An initial test of transportability to community clinics and clinicians.

Community clinic therapists were randomized to (a) brief training and supervision in cognitive–behavioral therapy (CBT) for youth depression or (b) usual care (UC). The therapists treated 57 youths (56% girls), ages 8–15, of whom 33% were Caucasian, 26% were African American, and 26% were Latino/Latina. Most youths were from low-income families and all had Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994) depressive disorders (plus multiple comorbidities). All youths were randomized to CBT or UC and treated until normal termination. Session coding showed more use of CBT by CBT therapists and more psychodynamic and family approaches by UC therapists. At posttreatment, depression symptom measures were at subclinical levels, and 75% of youths had no remaining depressive disorder, but CBT and UC groups did not differ on these outcomes. However, compared with UC, CBT was (a) briefer (24 vs. 39 weeks), (b) superior in parent-rated therapeutic alliance, (c) less likely to require additional services (including all psychotropics combined and depression medication in particular), and (d) less costly. The findings showed advantages for CBT in parent engagement, reduced use of medication and other services, overall cost, and possibly speed of improvement—a hypothesis that warrants testing in future research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Passive mode locking of InAlGaAs 1.3-/spl mu/m strained quantum wells extended cavity laser fabricated by quantum-well intermixing

We demonstrate continuous-wave operation and passive mode locking of extended cavity lasers fabricated in 1.3-/spl mu/m InAlGaAs strained multiple quantum-wells structure. Modal losses were measured for the passive section fabricated by quantum-well intermixing. Pulse duration of 1.7 ps was deduced from intensity autocorrelation measurement.     

Gain clamped erbium-doped fiber amplifiers-modeling and experiment

A spectrum-resolved numerical model for the gain clamped EDFA is developed. Good agreement between the model and experimental results is achieved. The model results reveal the gain, clamped gain spectral distribution and noise figure characteristics of the amplifier. The model is used to optimize the selection of the clamped amplifier laser wavelength and laser output coupling to minimize the noise figure     

The marginal cost of satellite versus in-center hemodialysis

Background: Despite increasing numbers of patients receiving hemodialysis in satellite units (SHD), the economic aspects have not been widely explored. A cost analysis of SHD and in‐center hemodialysis (ICHD) from a societal perspective was performed to establish the efficiencies associated with shifting resources and patients from ICHD to SHD. Methods: Costs were classified as fixed or variable and placed into categories. The resources for operating a SHD unit are the sum of two components: total fixed costs (TFC) and average variable cost (AVC) times SHD patient volume (Q). Using the TFC of a specific‐sized SHD unit and the difference in AVC between ICHD and SHD the number of patients needed (Q) in the SHD unit for financial viability was determined. The formula TFC = (AVC_ICHD ? AVC_SHD) X Q was used to determine the number of patients (Q) needed in a specific‐sized SHD unit such that the yearly cost of SHD treatment would be the same as ICHD treatment. Results: Our results show that SHD fixed costs can be fully offset if the volume of SHD patients is seven per year in a six‐station unit. SHD costs were lower for nursing and physician fees. Therefore, ICHD care variable costs were $11,374 more per patient year. SHD patients would also have lower travel costs, a mean cost saving of $12,364 per year. Conclusion: SHD can result in significant savings both to the health‐care system and to patients. Using the cost categories and formula presented, the number of patients needed in a specific‐sized satellite unit to realize cost savings was determined for our program. We found that these savings can offset the fixed investment needed to operate a SHD unit at modest patient volumes.