Climatic considerations in school building design in the hot–humid climate for reducing energy consumption

Energy-conscious design of school buildings can contribute to significant energy savings and improve the students’ learning environment. The purpose of this research is to formulate design recommendations for school buildings in the hot–humid climatic zone and assess the influence of different design variables on their energy consumption. A base-case classroom was constructed by taking commonly used values for each design variable. Using computer simulation techniques, these variables were modified one by one to find the value that minimized energy consumption, while keeping thermal and visual comfort in the room. Based on these tests, the recommended value for each design variable to achieve a high performance classroom, was determined. Comparative tests were done to determine which variables have greatest impact on the energy consumption and thermal comfort in the classroom, and how their absolute influence depends on the order of implementation of each improvement. A complex interdependence among the design variables was found, but strong conclusions for energy savings could still be reached.     

Processing and properties of nano‐ and macro‐hydroxyapatite/poly(ethylene‐co‐acrylic acid) composites

Hydroxyapatite (HAp)/poly(ethylene‐co‐acrylic acid) composites have been synthesized by a solution‐based method, using nanosized (n‐HAp) and coarse hydroxyapatite (c‐HAp) particles, respectively. X‐ray diffraction study has indicated the development of compressive and tensile stresses in composites because of the thermal expansion mismatch between the particles and polymer matrix. Fourier transform infrared absorption spectra and thermal analysis have showed the presence of strong interfacial bonding between the particles and polymer. The surface roughness and the homogeneous dispersion of HAp particles in the polymer matrix have been observed by scanning electron microscopy. A comparison in mechanical properties between composites prepared with n‐HAp and c‐HAp particles, respectively, has been studied. Nanosized particles contribute excellent improvement of mechanical properties of the composites rather than the coarse particles. The uniform dispersion of HAp particles, followed by the improvement in mechanical properties of the composite, provides a means of preparing HAp/polymer composites for low load‐bearing implant applications. POLYM. COMPOS., 27:633–641, 2006. © 2006 Society of Plastics Engineers     

Destruction of formic acid using high frequency cup horn reactor

Degradation of formic acid has been studied in a high frequency cup horn type reactor with an aim of understanding the effect of operating parameters on the destruction efficiency. The methodology used in the work serves as a useful guideline for the optimization exercise for the sonochemical reactors to establish a set of operating parameters at large scale operation for achieving maximum efficiency. Firstly energy efficiency of the reactor has been established as a function of the operating volume with an aim of optimization of the capacity of the reactor for maximum extent of degradation. It has been observed that maximum transfer of supplied power is obtained at 300 ml capacity and hence the actual degradation studies have been performed with this operational capacity. The effect of time of irradiation, initial concentration of the pollutant, stirrer speed, presence of sodium sulfite (to scavenge the initial dissolved oxygen) on the extent of degradation has been investigated. Maximum extent of degradation has been observed under the conditions of 500 mg/l initial concentration, 200 rpm stirrer speed and presence of initial dissolved oxygen (no sodium sulfite in the system). Process intensification studies have been carried out using sodium chloride over a range of initial concentration and it has been observed that maximum extent of degradation of formic acid is obtained at 4% NaCl concentration. Comparison has been also made with different sonochemical configurations operating at lower frequency of irradiation (typically in the range of 20-50 kHz) with an aim of comparing the efficacies of the reactor at equivalent power consumption.     

Kinetics of interaction of HIV fusion protein (gp41) with lipid membranes studied by real-time AFM imaging

One of the most important steps in the process of viral infection is a fusion between cell membrane and virus, which is mediated by the viral envelope glycoprotein. The study of activity of the glycoprotein in the post-fusion state is important for understanding the progression of infection. Here we present a first real-time kinetic study of the activity of gp41 (the viral envelope glycoprotein of human immunodeficiency virus—HIV) and its two mutants in the post-fusion state with nanometer resolution by atomic force microscopy (AFM). Tracking the changes in the phosphatidylcholine (PC) and phosphatidylcholine–phosphatidylserine (PC:PS) membrane integrity over one hour by a set of AFM images revealed differences in the interaction of the three types of protein with zwitterionic and negatively charged membranes. A quantitative analysis of the slow kinetics of hole formation in the negatively charged lipid bilayer is presented. Specifically, analysis of the rate of roughness change for the three types of proteins suggests that they exhibit different types of kinetic behavior.     

Transmittance from visible to mid infra-red in AZO films grown by atomic layer deposition system

We report transmittance and conductivity measurements of aluminum-doped zinc oxide films grown by atomic layer deposition. The results show that the films have 80–90% transmittance in the visible region and good transmittance in the infrared. To our knowledge, this is the first time that the transmittance of aluminum-doped zinc oxide is reported to extend beyond 2500–5000 nm. Following annealing, an optimal sheet resistance of 25 Ω/□ was obtained for a 575 nm thick film with a carrier density of 2.4 × 10²⁰ cm^?3 without compromising the transmittance in the visible regime.     

Chemo-Enzymatic Fluorescence Labeling Of Genomic DNA For Simultaneous Detection Of Global 5-Methylcytosine And 5-Hydroxymethylcytosine**

5-Methylcytosine and 5-hydroxymethylcytosine are epigenetic modifications involved in gene regulation and cancer. We present a new, simple, and high-throughput platform for multi-color epigenetic analysis. The novelty of our approach is the ability to multiplex methylation and de-methylation signals in the same assay. We utilize an engineered methyltransferase enzyme that recognizes and labels all unmodified CpG sites with a fluorescent cofactor. In combination with the already established labeling of the de-methylation mark 5-hydroxymethylcytosine via enzymatic glycosylation, we obtained a robust platform for simultaneous epigenetic analysis of these marks. We assessed the global epigenetic levels in multiple samples of colorectal cancer and observed a 3.5-fold reduction in 5hmC levels but no change in DNA methylation levels between sick and healthy individuals. We also measured epigenetic modifications in chronic lymphocytic leukemia and observed a decrease in both modification levels (5-hydroxymethylcytosine: whole blood 30 %; peripheral blood mononuclear cells (PBMCs) 40 %. 5-methylcytosine: whole blood 53 %; PBMCs 48 %). Our findings propose using a simple blood test as a viable method for analysis, simplifying sample handling in diagnostics. Importantly, our results highlight the assay‘s potential for epigenetic evaluation of clinical samples, benefiting research and patient management.     

Analysis of K-Transmit Dual-Receive Diversity with Cochannel Interferers over a Rayleigh Fading Channel

The need to combat the severe effects of fading and interferencein the rapidly increasing number of communication systemsproviding wireless services has motivated the study of diversityin the presence of interference.Hence the analysis of wireless systems with both transmit andreceive diversity and subject to cochannel interference is animportant tool for system design.We consider here a K-transmit dual-receive diversitycommunication systememploying K antennas for transmission and two antennasfor reception. The desired signal is corruptedby N interfering sources apart from additive whiteGaussian noise. The channel is Rayleigh fading.As a result, the channel matrix for the desired signaland the propagation vectors of the interferers havezero-mean complexGaussian entries; the entries are assumedto be independent and identically distributed.The complex receive weight vectorused for combining the received signalsis chosen so as to maximize the outputsignal-to-interference-plus-noiseratio (SINR).From the statistics of the channel matrix and thepropagation vectors of the interferers,we derive a closed-form expressionfor the probability density function (p.d.f.)of the maximum outputSINR. This p.d.f. can be used to obtainthe symbol errorprobability for different digital modulation schemes.     

Collaborative knowledge building using the Design Principles Database

In this study we describe a mechanism for supporting a community of learning scientists who are exploring educational technologies by helping them to share and collaboratively build design knowledge. The Design Principles Database (DPD) is intended to be built and used by this community to provide an infrastructure for participants to publish, connect, discuss and review design ideas, and to use these ideas to create new designs. The potential of the DPD to serve as a collaborative knowledge-building endeavor is illustrated by analysis of a CSCL study focused on peer-evaluation. The analysis demonstrates how the DPD was used by the researchers of the peer-evaluation study in three phases. In the first phase, design principles were articulated based on a literature review and contributed to the DPD. In the second phase, a peer-evaluation activity was designed based on these principles, and was enacted and revised in a three-iteration study. In the third phase, lessons learned through these iterations were fed back to the DPD. The analysis indicates that such processes can contribute to collaborative development of design knowledge in a community of the learning sciences. Readers of ijCSCL are invited to take part in this endeavor and share their design knowledge with the community.     

PSO Aided Adaptive Complementary Filter for Attitude Estimation

Attitude estimation is one of the core frame- works used for navigating an unmanned aerial vehicle from one place to the other. This paper presents an Euler-based non-linear complementary filter (CF) whose gain parameters are obtained using particle swarm optimization (PSO) technique. It relieves the user from feeding the K _P and K _I parameters manually and adjust these parameters automatically when the error between the attitude measured from accelerometer and the CF increases above a particular threshold. The measurement unit for this research consists of micro-electro-mechanical-systems (MEMS) based low cost tri-axial rate gyros, accelerometers and magnetometers, without resorting to global positioning system (GPS) data. The efficiency of the CF is experimentally investigated with the help of reference attitude and the raw sensor data obtained from commercial inertial measurement unit (IMU). Simulation results based on the test data show that the proposed PSO aided non-linear complementary filter (PNCF) can automatically obtain the required gain parameters and exhibits promising performance for attitude estimation.     

An Examination of Determinants of Software Testing and Project Management Effort

Software estimation research has primarily focused on software effort involved in direct software development. As more and more organizations buy instead of building software, more effort is spent on software testing and project management. In this empirical study, the effect of program duration, computer platform, and software development tool (SDT) on program testing effort and project management effort is studied. The study results point to program duration and software tool as significant determinants of testing and management effort. Computer platform, however, does not have an effect on testing and management effort. Furthermore, the mean testing effort for third generation (3G) development environment was significantly higher than the mean testing effort for fourth generation (4G) environments that used IDE. In addition, the management effort for 4G environment projects without the use of IDE was lower than nonprogramming report generation projects.