7,489 research outputs found
Thermal comfort guidelines for production spaces within multi-storey garment factories located in Bangladesh
This research presents extensive field data on indoor thermal conditions along with workers' comfort votes taken at their workstations within three existing multi-storied garment factories during the three seasons (cool-dry, hot-dry and warm-humid) of Bangladesh. The main objective of the study was to observe the impact of thermal conditions on workers’ indoor thermal perception during each season of a year and from this identify thermal comfort guidelines (e.g. neutral temperatures, comfort ranges, preferred airspeeds and directions) to execute their production work comfortably. Subjective votes were collected from a total of 908 workers with the thermal data, physiological data and adaptive measures recorded simultaneously. Statistical analyses revealed that workers can accept a wider and relatively higher comfort range than the predicted band during cool-dry and hot-dry seasons, for instance, 22.7–29.1 °C and 22.3–30.4 °C respectively. A narrower comfort band (e.g. 28.7–30.9 °C), close to the predicted range, was found during the warm-humid season, which can be maintained by reducing radiant temperature and elevating airspeed. Further analyses indicated that workers prefer a mean airspeed of 0.3 m/s and comfort range of 0–3.0 m/s specific to their activities preferably from inlets located on south, north and east facades while upward and downward air movement, from for example ceiling fans, causes a rise of air temperature in the occupational zone and thermal discomfort. This research also suggested that the maximum distances of workstations from the ventilation inlets (windows) should be maintained at 12–18 m for sufficient cross ventilation, personal controls and adaptive opportunities to help maintain preferred thermal condition
A Low Cost Two-Tier Architecture Model For High Availability Clusters Application Load Balancing
This article proposes a design and implementation of a low cost two-tier
architecture model for high availability cluster combined with load-balancing
and shared storage technology to achieve desired scale of three-tier
architecture for application load balancing e.g. web servers. The research work
proposes a design that physically omits Network File System (NFS) server nodes
and implements NFS server functionalities within the cluster nodes, through Red
Hat Cluster Suite (RHCS) with High Availability (HA) proxy load balancing
technologies. In order to achieve a low-cost implementation in terms of
investment in hardware and computing solutions, the proposed architecture will
be beneficial. This system intends to provide steady service despite any system
components fails due to uncertainly such as network system, storage and
applications.Comment: Load balancing, high availability cluster, web server cluster
Comparative Study on Agile software development methodologies
Today-s business environment is very much dynamic, and organisations are
constantly changing their software requirements to adjust with new environment.
They also demand for fast delivery of software products as well as for
accepting changing requirements. In this aspect, traditional plan-driven
developments fail to meet up these requirements. Though traditional software
development methodologies, such as life cycle-based structured and object
oriented approaches, continue to dominate the systems development few decades
and much research has done in traditional methodologies, Agile software
development brings its own set of novel challenges that must be addressed to
satisfy the customer through early and continuous delivery of the valuable
software. It is a set of software development methods based on iterative and
incremental development process, where requirements and development evolve
through collaboration between self-organizing, cross-functional teams that
allows rapid delivery of high quality software to meet customer needs and also
accommodate changes in the requirements. In this paper, we significantly
identify and describe the major factors, that Agile development approach
improves software development process to meet the rapid changing business
environments. We also provide a brief comparison of agile development
methodologies with traditional systems development methodologies, and discuss
current state of adopting agile methodologies. We speculate that from the need
to satisfy the customer through early and continuous delivery of the valuable
software, Agile software development is emerged as an alternative to
traditional plan-based software development methods. The purpose of this paper,
is to provide an in-depth understanding, the major benefits of agile
development approach to software development industry, as well as provide a
comparison study report of ASDM over TSDM.Comment: 25 pages, 25 images, 86 references used, with authors biographie
Itinerant and local-moment magnetism in EuCr2As2 single crystals
We report on the crystal structure, physical properties, and electronic
structure calculations for the ternary pnictide compound EuCr2As2. X-ray
diffraction studies confirmed that EuCr2As2 crystalizes in the ThCr2Si2-type
tetragonal structure (space group I4/mmm). The Eu ions are in a stable divalent
state in this compound. Eu moments in EuCr2As2 order magnetically below Tm = 21
K. A sharp increase in the magnetic susceptibility below Tm and the positive
value of the paramagnetic Curie temperature obtained from the Curie-Weiss fit
suggest dominant ferromagnetic interactions. The heat capacity exhibits a sharp
{\lambda}-shape anomaly at Tm, confirming the bulk nature of the magnetic
transition. The extracted magnetic entropy at the magnetic transition
temperature is consistent with the theoretical value Rln(2S+1) for S = 7/2 of
the Eu2+ ion. The temperature dependence of the electrical resistivity
\r{ho}(T) shows metallic behavior along with an anomaly at 21 K. In addition,
we observe a reasonably large negative magneto-resistance (~ -24%) at lower
temperature. Electronic structure calculations for EuCr2As2 reveal a moderately
high density of states of Cr-3d orbitals at the Fermi energy, indicating that
the nonmagnetic state of Cr is unstable against magnetic order. Our density
functional calculations for EuCr2As2 predict a G-type AFM order in the Cr
sublattice. The electronic structure calculations suggest a weak interlayer
coupling of the Eu moments.Comment: 9 pages, 7 figure
Application of Islamic Consumer Theory: an Empirical Analysis in the Context of Bangladesh
One of the main goals of economics is to satisfy the wants of consumer. Like as conventional economics, Islamic economics has also its own law of consumption which is superior to that of conventional economics. This paper presents an empirical survey report on the application of Islamic consumer theory in Bangladesh.The survey is conducted on 184 graduate students of economics from university of Dhaka, Bangladesh. Besides, the consumption framework of Islamic economics has been discussed in this paper. The research finds that, the majority percent of respondents consider Halal (lawful), Haram (unlawful), economic disadvantages of other consumers, scope of reward and punishment in hereafter life (life after death) in their consumptions and other economic activities. The report explores that, though the wants is unlimited, the respondents are capable to control their wants and choose moderate and simple standard of living. In addition, they mentioned that, the use of interest is not essential to run economic activities and interest free economy is possible. It is found that, a large proportion of the respondents did not study Islamic economics due to unavailability of the reading materials in spite of having their interest while half of the respondents read it. Finally, the opinion is found that, religious and ethical instruments (Zakat, donation, hereafter life etc.) should be included in the syllabus of modern economics in school, college and university level. The findings satisfy the assumptions of Islamic consumption framework. Finally, it presents the problems, prospects and recommendations to apply the Islamic consumer theory in Bangladesh
Valence Fluctuation in CeMo2Si2C
We report on the valence fluctuation of Ce in CeMoSiC as studied
by means of magnetic susceptibility , specific heat , electrical
resistivity and x-ray absorption spectroscopy. Powder x-ray
diffraction revealed that CeMoSiC crystallizes in
CeCrSiC-type layered tetragonal crystal structure (space group
\textit{P4/mmm}). The unit cell volume of CeMoSiC deviates from the
expected lanthanide contraction, indicating non-trivalent state of Ce ions in
this compound. The observed weak temperature dependence of the magnetic
susceptibility and its low value indicate that Ce ions are in valence
fluctuating state. The formal Ce valence in CeMoSiC
= 3.11 as determined from x-ray absorption spectroscopy
measurement is well bellow the value 3.4 in
tetravalent Ce compound CeO. The temperature dependence of specific heat
does not show any anomaly down to 1.8 K which rules out any magnetic ordering
in the system. The Sommerfeld coefficient obtained from the specific heat data
is = 23.4 mJ/mol\,K. The electrical resistivity follows the
behavior in the low temperature range below 35 K confirming a Fermi
liquid behavior. Accordingly both the Kadowaki Wood ratio and
the Sommerfeld Wilson ratio are in the range expected for
Fermi-liquid systems. In order to get some information on the electronic
states, we calculated the band structure within the density functional theory,
eventhough this approach is not able to treat 4f electrons accurately. The
non- electron states crossing the Fermi level have mostly Mo 4d character.
They provide the states with which the 4f sates are strongly hybridized,
leading to the intermediate valent state.Comment: 18 pages, 10 figures Submitted to Journal of Alloys and Compound
Opposing roles for DNA replication initiator proteins ORC1 and CDC6 in control of Cyclin E gene transcription
Newly-born cells either continue to proliferate or exit the cell division cycle. This decision involves delaying expression of Cyclin E that promotes DNA replication. ORC1, the Origin Recognition Complex (ORC) large subunit, is inherited into newly-born cells after it binds to condensing chromosomes during the preceding mitosis. We demonstrate that ORC1 represses Cyclin E gene (CCNE1) transcription, an E2F1 activated gene that is also repressed by the Retinoblastoma (RB) protein. ORC1 binds to RB, the histone methyltransferase SUV39H1 and to its repressive histone H3K9me3 mark. ORC1 cooperates with SUV39H1 and RB protein to repress E2F1-dependent CCNE1 transcription. In contrast, the ORC1-related replication protein CDC6 binds Cyclin E-CDK2 kinase and in a feedback loop removes RB from ORC1, thereby hyper-activating CCNE1 transcription. The opposing effects of ORC1 and CDC6 in controlling the level of Cyclin E ensures genome stability and a mechanism for linking directly DNA replication and cell division commitment
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