1,522 research outputs found
To what extent can solar control be effective in enhancing indoor comfort in a fully glazed office building?
It is acknowledged that people spend almost 90 percent of their time in indoor spaces. Therefore, achieving a comfortable indoor environment that encourages productivity is crucial, particularly in office buildings. This paper investigates the design and performance of a modern office building in London characterized by fully glazed facades of open plan office spaces with no natural ventilation. The purpose of the research is to investigate the correlations between the control of direct solar radiation access and the effect on occupants' thermal comfort in the summer followed by assessing the potential effect of the application of passive solar shading on thermal comfort levels in the office spaces. The research methodology involves a survey questionnaire undertaken with employees of the office building, followed by dynamic thermal modelling of the building using Integrated Environmental Solutions (IES) software. The questionnaire has been designed to understand occupants' experiences within their office spaces and their strategies to improve the indoor environment. Furthermore, IES modelling and simulation provide in depth understanding of the building thermal performance and investigating the solar shading strategies. Overall, 66 questionnaire forms were completed where preliminary results demonstrated that most employees relied heavily on secondary cooling and heating systems to adjust the indoor air temperature for more satisfactory thermal comfort levels in their office spaces. The building modelling and simulation is used to quantify the direct solar radiation accessing the office space, the risks of overheating and the potential impact of solar control on occupants' indoor comfort. The findings from this study demonstrate the potentially high hours of discomfort in the summer within the office spaces mainly due to the lack of control of direct solar access through the extensive area of glazed facades. In order to maintain the thermal environment within the comfort level threshold in the warmer seasons a solar shading strategy should be considered
Vibration Signature of Normal and Notched Tooth Gear Pump
Gear pumps are critical devices in many industrial applications. An unexpected failure of the gear pump may cause significant effect on its performance. Consequently, there will be economic losses. As a result of that, fault diagnosis in gears has been the subject of intensive research. Vibration analysis has been used as an effective tool in machines diagnosis and in machinery maintenance decisions. As a rule, an increased vibration level is a warning form before failure or breakdown. By measuring and analyzing the gear pump vibration, it is possible to determine both the nature and severity of the defect, and hence predict the machine’s failure. The vibration signal of a gear pump carries the signature of the fault in the gears, and early fault detection of the gear pump is possible by analyzing the vibration signal using different signal processing techniques. This paper presents, experimentally, the external gear pump signature for normal and faulty gear pumps at different rotational speeds (1080, 1200, and 1439rpm). The considered faults herein are two different notches on one of the pump teeth— small notch and large notch. The paper concludes that features of the vibration are different with the notch shape and the rotational speed. The amplitude of vibration increases by increasing both rotational speed and notch size
Perilaku Masyarakat dalam Pengelolaan Kesehatan Lingkungan (Studi di Desa Segiguk sebagai Salah Satu Desa Penyangga Kawasan Hutan Suaka Margasatwa Gunung Raya Ogan Komering Ulu Selatan)
Penelitian ini bertujuan untuk menganilisis tentang pengelolaan lingkungan pemukiman di salah satu desa penyangga kawasan Hutan Suaka Margasatwa Gunung Raya. Penelitian ini juga bertujuan untuk mengetahui partisipasi masyarakat dalam mengelola dan mempertahankan kualitas lingkungan kawasan yang dilindungi pemerintah. Selain itu, permasalahan kesehatan yang berpotensial terjadi di wilayah tersebut , akibat pengelolaan lingkungan, juga menjadi perhatian pada penelitian ini. Penelitian ini merupakan penelitian studi kasus dengan metode penelitian deskriptif kualitatif. Parameter yang diamati adalah bentuk partisipasi masyarakat dalam pengelolaan lingkungan sehat terhadap penggunaan air bersih, struktur rumah sehat, keluarga dengan kepemilikan sarana sanitasi dasar dan tenpat umum dan pengelolaan makanan.Bentuk partisipasi tersebut dapat diamati pada perilaku masyarakat yang merupakan implementasi dari persepsi dan pemahaman masyarakat mengenai hal tersebut
Pilot Scale of Microalgal Production Using Photobioreactor
Microalgal gained much interest as a promising sustainable feedstock for the production of food, feed, bulk chemicals and biofuels. Pilot scale of microalgal is needed to bridge the gap between laboratory scale research and commercial application. Commercial applications of microalgal have been used for a wide array of functions including, pharmaceutical, health sector, nutraceutical, cosmetics and agriculture. Numerous photobioreactors (PBRs) of different volume and shapes have been designed. Cost of PBR has a major influence on production cost for large scale biomass. There are several ways to reduce production cost depends on the type of algal strain, type of PBRs, CO2 and the production technology of the biomass. Dilution rate is an important factor, which affects the biomass productivity, rate and ultimately what needs to be maximized
Transport of dust and anthropogenic aerosols across Alexandria, Egypt
The flow of pollutants from Europe and desert dust to Europe from the Sahara desert both affects the air quality of the coastal regions of Egypt. As such, measurements from both ground and satellite observations assume great importance to ascertain the conditions and flow affecting the Nile Delta and the large city of Alexandria. We note that special weather conditions prevailing in the Mediterranean Sea result in a westerly wind flow pattern during spring and from North to South during the summer. Such flow patterns transport dust-loaded and polluted air masses from the Sahara desert and Europe, respectively, through Alexandria, and the Nile Delta in Egypt. We have carried out measurements acquired with a ground- based portable sun photometer (Microtops II) and the satellite-borne TERRA/Moderate Resolution Imaging Spectroradiometer (MODIS) sensor during the periods of October 1999–August 2001 and July 2002–September 2003. These measurements show a seasonal variability in aerosol optical depth (AOD) following these flow patterns. Maximum aerosol loadings accompanied by total precipitable water vapor (W) enhancements are observed during the spring and summer seasons. Pronounced changes have been observed in the Ã…ngström exponent (α) derived from ground-based measurements over Alexandria (31.14° N, 29.59° E) during both dust and pollution periods. We have followed up the observations with a 3-day back-trajectories model to trace the probable sources and pathways of the air masses causing the observed aerosol loadings. We have also used other NASA model outputs to estimate the sea salt, dust, sulfates and black carbon AOD spatial distributions during different seasons. Our results reveal the probable source regions of these aerosol types, showing agreement with the trajectory and Ã…ngström exponent analysis results. It is confirmed that Alexandria is subjected to different atmospheric conditions involving dust, pollution, mixed aerosols and clean sky
New microplanktonic biostratigraphy and depositional sequences across the Middle-Late Eocene and Oligocene boundaries in eastern Jordan
The first detailed calcareous nannofossil and planktonic foraminiferal
biostratigraphic and integrated lithofacies analyses of the Eocene–Oligocene
transition at the Qa’ Faydat ad Dahikiya area in the Eastern Desert of Jordan, on
the border with Saudi Arabia, is presented. Three calcareous nannofossil zones
namely: Discoaster saipanensis (NP17), Chiasmolithus oamaruensis (NP18) and
Ericsonia subdisticha (NP21), and three planktonic foraminiferal zones: upper part
of Truncorotaloides rohri (E13), Globigerinatheka semiinvoluta (E14) and Cassigerinella
chipolensis/ Pseudohastigerina micra (O1) are identified.
Calcareous nannofossil bioevents recorded in the present study show numerous
discrepancies with the Standard biostratigraphic zonal schemes to detect
the Middle/Upper Eocene boundary (e.g. the highest occurrences (HOs) of
Chiasmolithus solitus, C. grandis, and lowest occurrences (LOs) of C. oamaruensis,
Isthmolithus recurvus are not considered reliable markers for global correlation). The
Middle/Upper Eocene boundary occurs in the current study above the extinctions
of large muricate planktonic foraminifera (large Acarinina and Truncorotaloides
spp.) which coincide within the equivalent calcareous nannofossil NP18 Zone.
These microplanktonic bioevents seem to constitute more reliable markers for the
base of the Upper Eocene in different provinces. The uppermost portion of the
Middle Eocene is characterized by an observed drop in faunal content and, most
likely, primarily denotes the effect of the major fall in eustatic sea level.
A major unconformity (disconformity) marked by a mineralized hardground
representing a lowstand is recorded in the present study at the Eocene–Oligocene
transition that reveals an unexpected ca. 2.1 Myr duration, separating Eocene
(NP18/E14 zones) from Oligocene (NP21/O1 zones). Furthermore, the microfossil
turnover associated with a rapid decline of the microfossil assemblages shows
a distinct drop in diversity and abundance towards the Eocene/Oligocene
unconformity and is associated with a sharp lithological break marked, at the
base, by a mineralized hardground representing a major sequence boundary.
These bioevents, depositional sequences and the depositional hiatus correlate
well with different parts of the Arabian and African plates, but the magnitude of
the faunal break differs from place to place as a result of intraplate deformation
during the regional Oligocene regression of Neo-Tethys on the northern Arabian
Plate. The presence of the Lower Oligocene shallow-marine calcareous planktonic
assemblages in the study area indicate that communication between the eastern
and western provinces of the western Neo-Tethys region still existed at this time
Ground-based measurements of UV Index (UVI) at Helwan
AbstractOn October 2010 UV Index (UVI) ground-based measurements were carried out by weather station at solar laboratory in NRIAG. The daily variation has maximum values in spring and summer days, while minimum values in autumn and winter days. The low level of UVI between 2.55 and 2.825 was found in December, January and February. The moderate level of UVI between 3.075 and 5.6 was found in March, October and November. The high level of UVI between 6.7 and 7.65 was found in April, May and September. The very high level of UVI between 8 and 8.6 was found in June, July and August. High level of radiation over 6months per year including 3months with a very high level UVI. According to the equation {UVI=a[SZA]b} the UVI increases with decreasing SZA by 82% on a daily scale and 88% on a monthly scale. Helwan exposure to a high level of radiation over 6months per year including 3months with a very high level UVI, so it is advisable not to direct exposure to the sun from 11am to 2:00pm
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