446 research outputs found
Fire Protection Analysis of a K-12 Classroom Building
The report evaluates the fire protection features of a K-12 classroom building (Bldg. B) in San Bernardino County, California. Bldg. B is a two-story Type V-A light timber frame construction. At the time of this report’s composition, Bldg. B is undergoing modernization construction. The fire protection analysis of this building consists of prescriptive and performance portions.
The prescriptive analysis verifies the compliance of building egress, passive, and active protection features with the 2019 edition of California Codes of Regulations Title 24 (Title 24) and Title 24-adopted National Fire Protection Association (NFPA) standards. The analysis comprises of four sections: egress, structural analysis, fire alarm design, and sprinkler system analysis. The egress section describes the occupancy classifications and assesses the occupant loads, the required width for exits and exit access doorways, the number of available fire escapes, exit separation distance, and interior finishes. The structural analysis section focuses on the modernization expansion area increase, the building elements’ fire-resistance rating, and fire separation requirements. The fire alarm section surveys the location of alarm devices, determines the spacing requirements, identifies active smoke control in place, and diagnoses the secondary power supply. The sprinkler system analysis section checks the fire suppression device coverage and the required hydraulic pressure for the chosen remote design areas. Overall, the fire protection features in Bldg. B follow the prescriptive codes of regulation in effect at the time of modernization design, and implicit safety is accomplished.
The performance-based analysis gauges the effectiveness of prescriptive active fire protection systems in providing explicit safety to occupants in Bldg. B using three design fires. Locations of these fires are selected based on potential life safety impacts. The heat release rates of the design fires reference fuel load data from SFPE Handbook and Nuclear Regulatory Commission (NUREG) literature.
To achieve explicit safety, the available safe egress time (ASET) for a design fire must exceed the required safe egress time (RSET).
Before ASET is estimated, a set of tenability criteria on visibility, toxicity, radiant heat exposure, and flashover has to be established. The exceedance of any one tenability criterion signifies the expiration of ASET. Computational fire dynamics is used to find the ASET of a design fire.
RSET is based on egress component width, space density, occupant familiarity with the building, and population size. Using hydraulic flow model, NIST Egress Estimator, and Thunderhead Engineering’s Pathfinder software, the full-evacuation time for the entire building is predicted to be 4.87 minutes. RSET is then further refined for individual design fire scenario.
The first design fire (DF-1) is on the first-floor Flex Studio 2 137. Flex Studio 2 137 and the adjacent Flex Studio 1 136 are significant exit access areas where occupants of nearby classrooms and north wing 2nd-floor occupants must go through to reach building exits. If egress is disabled for the area, occupants in nearby spaces would be trapped. Using hydraulic flow model and Pathfinder, RSET for DF-1 is calculated to be 2.81 minutes. DF-1 is then put into Pyrosim to estimate ASET. After analyzing simulation results, DF-1 ASET is found to be visibility driven, as incapacitation, radiant heat exposure adverse outcome, and flashover are unlikely. When significant sub-4m visibility pockets appear along the wall around 3.14 minutes, visibility tenability expires for DF-1. As such, for DF-1, ASET (3.14 minutes) is greater than RSET (2.81 minutes); explicit safety is achievable. Another ASET vs RSET analysis is performed for the 2nd-floor because smoke may travel through the now unenclosed Stair B unimpeded and impair egress. Pyrosim predicts the visibility would remain above 30 meters during RSET. As such, ASET is also greater than RSET for the 2nd-floor spaces above DF-1.
The second fire (DF-2) is in the library reading area. An ASET vs RSET comparison is done, and occupants would be able to escape in time through the available exits. The concerns then become property damage mitigation and life safety in adjacent spaces. Using Pyrosim, the sprinkler system is predicted to activate at 61 seconds, keeping the HRR at 400 kW. With the activation of automatic fire sprinklers, the risks of flashover and property damage are low.
The third fire (DF-3) is in the first-floor electrical room near the elevator shaft and a main building exit. The concern is a possible flashover. A two-zone model is constructed in CFAST which predicts that the sprinkler system would activate 45 seconds and freeze the HRR at 130 kW, far below the lowest predicted flashover HRR of 1053 kW. Therefore, flashover is not expected and DF-3’s impact on adjacent space egress is minimal.
The results of performance analysis are favorable. Explicit safety is attainable with functional active fire protection systems
Growth, characterization and design of INP-based strained-layer multiple quantum wells for optical modulator devices
Experimental methods and background -- Sample cleaning -- Growth of strained-layer, InP-based thin film materials by MOVPE -- Structural characterization by x-ray diffraction -- Wet chemical etching of InP in HCI-based solutions -- Au-based contact contact metallizations on InP -- Measurement of field-dependent absorption curves by photocurrent detection -- Detailed balance efficiency limit in quantum well solar cells -- Strain and relaxation in multiple quantum well stacks -- Band alignment engineering for the quantum-confined stark effect -- Band alignment engineering for high-speed, low drive field quantum-confined stark effect devices
Review of Design and Build Construction: Descriptive Statistics in one of the South East Asia country
In the area of the construction sector, the primary concern is economic growth. There are many issues and challenges associated with it. The growth and rapid development of this industry put their players, mainly the construction firms feeling the heat by competing with each other. The main challenge is the completion period for a particular project. This study was done in Manila, Philippines, where Design and Build (D&B) method has gained much interest and considered very important today. The rise of new innovative systems saw the emergence of new factors in the construction industry that will become future adoption. This study focuses on factors affecting the successful completion period of the construction industry, whereby it is very crucial for the country's economic and market development. A quantitative research methodology was applied in this study. A total of 967 survey questionnaires sent out, and only 396 respondents fit to be analysed. Respondents involved were contractors, consultants, and developers. It was learned that critical success factors in project management play significant roles in driving projects to examine the determinants of success completion time of Design & Build construction projects. Findings from this study shall be used by the authority in drafting a policy guideline for future construction development. It is hoped that this study provides a better understanding of construction challenges for future undertaking
Automated Long-Term Monitoring of Parallel Microfluidic Operations Applying a Machine Vision-Assisted Positioning Method
As microfluidics has been applied extensively in many cell and biochemical applications, monitoring the related processes is an important requirement. In this work, we design and fabricate a high-throughput microfluidic device which contains 32 microchambers to perform automated parallel microfluidic operations and monitoring on an automated stage of a microscope. Images are captured at multiple spots on the device during the operations for monitoring samples in microchambers in parallel; yet the device positions may vary at different time points throughout operations as the device moves back and forth on a motorized microscopic stage. Here, we report an image-based positioning strategy to realign the chamber position before every recording of microscopic image. We fabricate alignment marks at defined locations next to the chambers in the microfluidic device as reference positions. We also develop image processing algorithms to recognize the chamber positions in real-time, followed by realigning the chambers to their preset positions in the captured images. We perform experiments to validate and characterize the device functionality and the automated realignment operation. Together, this microfluidic realignment strategy can be a platform technology to achieve precise positioning of multiple chambers for general microfluidic applications requiring long-term parallel monitoring of cell and biochemical activities
Treatment outcome and prognostic factor analysis in transplant-eligible Chinese myeloma patients receiving bortezomib-based induction regimens including the staged approach, PAD or VTD
BACKGROUND: We have reported promising outcomes using a staged approach, in which bortezomib/thalidomide/dexamethasone was used only in 14 patients with suboptimal response to VAD (vincristine/adriamycin/dexamethasone) before autologous stem cell transplantation (ASCT). Here we compared the outcomes of the staged approach with frontline PAD (bortezomib/doxorubicin/dexamethasone) or VTD (bortezomib/thalidomide/dexamethasone) induction, and analysed prognostic factors for outcome. PATIENTS AND METHODS: Ninety-one transplant-eligible Chinese patients received three induction regimens prior to ASCT [staged approach (N = 25), PAD (N = 31), VTD (N = 35)]. and received thalidomide maintenance for 2 years post-ASCT. RESULTS: 43 (47.3%) patients had International Staging System (ISS) III disease. By an intention-to-treat analysis, the overall CR/nCR rate were 37.4% post-induction, and 62.6% post-ASCT. Five-year overall (OS) and event-free (EFS) survivals were 66% and 45.1%. There was no difference of the post-induction CR/nCR rate, EFS or OS between patients induced by these three regimens. Moreover, ISS III disease did not affect CR/nCR rates. Multivariate analysis showed that ISS and post-ASCT CR/nCR impacted OS while ISS and post-induction CR/nCR impacted EFS. CONCLUSIONS: These three induction regimens produced comparable and favorable outcomes in myeloma. The unfavorable outcome of ISS stage III persisted despite upfront/early use of bortezomib. CR/nCR predicted favorable survivals
Irinotecan or FOLFIRI for 2nd line colorectal
Background Second-line treatment with irinotecan for advanced or metastatic colorectal cancer prolongs survival. It is uncertain whether irinotecan is better administered with 5- fluorouracil or alone in patients previously treated with a fluoropyrimidine. We compared toxicity (particularly diarrhoea), quality of life, and efficacy of combination chemotherapy and irinotecan in these patients. Methods In DaVINCI, a randomised phase II trial, patients with advanced colorectal cancer were randomly allocated to: combination therapy (FOLFIRI), irinotecan (180 mg/m2 IV over 90 min, day 1), 5-fluorouracil (400 mg/m2 IV bolus and 2400 mg/m2 by 46-hour infusion from day 1) and folinic acid (20 mg/m2 IV bolus, day 1), 2-weekly; or single-agent, irinotecan (350 mg/m2 IV over 90 min), 3-weekly. Toxicity was evaluated every treatment cycle; QOL and response 6 weekly. Analysis was by intention to treat. Results were also combined with those of other trials. Findings We randomised 44 patients to combination and 45 to single-agent. The most common toxicity was complete alopecia (single-agent 37%, combination 14%, P<0.02). Eight patients in the irinotecan arm and 4 in the combination arm had grade 3–4 diarrhoea (P=0.24). The treatment groups did not differ significantly in overall QOL changes, response rate, or progression free or overall survival. In a systematic review of 29 trials of second-line irinotecan-based treatment, single-agent irinotecan was associated with more diarrhoea and alopecia than the combination, but efficacy was similar. Interpretation Combination treatment compared with single-agent irinotecan appears to reduce the rateof complete alopecia and diarrhoea without compromising efficacy on clinical outcomes.Australasian Gastro-Intestinal Trials Grou
Altruism and the evolution of resource generalism and specialism
The evolution of resource specialism and generalism has attracted widespread interest. Evolutionary drivers affecting niche differentiation and resource specialization have focused on the role of trade-offs. Here, however, we explore how the role of cooperation, mediated through altruistic behaviors, and classic resource–consumer dynamics can influence the evolution of resource utilization. Using an evolutionary invasion approach, we investigate how critical thresholds in levels of altruism are needed for resource specialization to arise and be maintained. Differences between complementary (essential) and substitutable resources affect the evolution of resource generalists. The strength of resource preferences coupled with the levels of altruism are predicted to influence the evolution of generalism. Coupling appropriate evolutionary game and ecological dynamics lead to novel expectations in the feedbacks between social behaviors and population dynamics for understanding classic ecological problems
The effects of bending speed on the lumbo-pelvic kinematics and movement pattern during forward bending in people with and without low back pain
Abstract Background Impaired lumbo-pelvic movement in people with low back pain during bending task has been reported previously. However, the regional mobility and the pattern of the lumbo-pelvic movement were found to vary across studies. The inconsistency of the findings may partly be related to variations in the speed at which the task was executed. This study examined the effects of bending speeds on the kinematics and the coordination lumbo-pelvic movement during forward bending, and to compare the performance of individuals with and without low back pain. Methods The angular displacement, velocity and acceleration of the lumbo-pelvic movement during the repeated forward bending executed at five selected speeds were acquired using the three dimensional motion tracking system in seventeen males with low back pain and eighteen males who were asymptomatic. The regional kinematics and the degree of coordination of the lumbo-pelvic movement during bending was compared and analysed between two groups. Results Significantly compromised performance in velocity and acceleration of the lumbar spine and hip joint during bending task at various speed levels was shown in back pain group (p < 0.01). Both groups displayed a high degree of coordination of the lumbo-pelvic displacement during forward bending executed across the five levels of speed examined. Significant between-group difference was revealed in the coordination of the lumbo-pelvic velocity and acceleration (p < 0.01). Asymptomatic group moved with a progressively higher degree of lumbo-pelvic coordination for velocity and acceleration while the back pain group adopted a uniform lumbo-pelvic pattern across all the speed levels examined. Conclusions The present findings show that bending speed imposes different levels of demand on the kinematics and pattern of the lumbo-pelvic movement. The ability to regulate the lumbo-pelvic movement pattern during the bending task that executed at various speed levels was shown only in pain-free individuals but not in those with low back pain. Individuals with low back pain moved with a stereotyped strategy at their lumbar spine and hip joints. This specific aberrant lumbo-pelvic movement pattern may have a crucial role in the maintenance of the chronicity in back pain
Carboxyl-terminal truncated HBx regulates a distinct microRNA transcription program in Hepatocellular carcinoma development
Background: The biological pathways and functional properties by which misexpressed microRNAs (miRNAs) contribute to liver carcinogenesis have been intensively investigated. However, little is known about the upstream mechanisms that deregulate miRNA expressions in this process. In hepatocellular carcinoma (HCC), hepatitis B virus (HBV) X protein (HBx), a transcriptional trans-activator, is frequently expressed in truncated form without carboxyl-terminus but its role in miRNA expression and HCC development is unclear. Methods: Human non-tumorigenic hepatocytes were infected with lentivirus-expressing full-length and carboxyl-terminal truncated HBx (Ct-HBx) for cell growth assay and miRNA profiling. Chromatin immunoprecipitation microarray was performed to identify the miRNA promoters directly associated with HBx. Direct transcriptional control was verified by luciferase reporter assay. The differential miRNA expressions were further validated in a cohort of HBV-associated HCC tissues using real-time PCR. Results: Hepatocytes expressing Ct-HBx grew significantly faster than the full-length HBx counterparts. Ct-HBx decreased while full-length HBx increased the expression of a set of miRNAs with growth-suppressive functions. Interestingly, Ct-HBx bound to and inhibited the transcriptional activity of some of these miRNA promoters. Notably, some of the examined repressed-miRNAs (miR-26a, -29c, -146a and -190) were also significantly down-regulated in a subset of HCC tissues with carboxyl-terminal HBx truncation compared to their matching non-tumor tissues, highlighting the clinical relevance of our data. Conclusion: Our results suggest that Ct-HBx directly regulates miRNA transcription and in turn promotes hepatocellular proliferation, thus revealing a viral contribution of miRNA deregulation during hepatocarcinogenesis. © 2011 Yip et al.published_or_final_versio
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