1,785 research outputs found
The responses of secondary forest tree seedings to soil enrichment in Peninsular Malaysia : an experimental approach
Secondary forests are gaining prominence in tropical landscapes, but in areas adjacent to agricultural land the mix of species found in them is likely to be influenced by high rates of fertilisation and nutrient run-off. We conducted a pot experiment on three secondary forest species, Glochidion obscurum, Lagerstroemia speciosa and Vitex pinnata, to ascertain their response to nutrient addition. We used three treatments, (1) control (no fertilizer addition); (2) addition of 1 g of rock phosphate; and (3) addition of 1 g NPK, and found that G. obscurum and L. speciosa increased their growth when levels of nitrogen, phosphorus and potassium were
increased, indicating evolutionary adaptation to use a high resource strategy. However, V. pinnata did not show the same pattern. It is, therefore, possible that on-going fertilization of low-lying secondary forests will produce growing conditions that lead to the reduction of non
responsive species such as V. pinnata and favour others, such as G. obscurum and L. speciosa, at least in the early stages of forest succession
A framework for producing gbXML building geometry from Point Clouds for accurate and efficient Building Energy Modelling
The industrial sector accounts for 17% of end-use energy in the United Kingdom, and 54% globally. Therefore, there is substantial scope to accurately simulate and efficiently assess potential energy retrofit options for industrial buildings to lower end use energy. Due to potentially years of facility renovation and expansion Building Energy Modelling, also called Building Energy Simulation, applied to industrial buildings poses a complex challenge; but it is an important opportunity for reducing global energy demand especially considering the increase of readily available computational power compared with a few years ago. Large and complex industrial buildings make modelling existing geometry for Building Energy Modelling difficult and time consuming which impacts analysis workflow and assessment options available within reasonable budgets. This research presents a potential framework for quickly capturing and processing as-built geometry of a factory, or other large scale buildings, to be utilised in Building Energy Modelling by storing the geometry in a green building eXtensible Mark-up Language (gbXML) format, which is compatible with most commercially available Building Energy Modelling tools. Laser scans were captured from the interior of an industrial facility to produce a Point Cloud. The existing capabilities of a Point Cloud processing software and previous research were assessed to identify the potential development opportunities to automate the conversion of Point Clouds to building geometry for Building Energy Modelling applications. This led to the novel identification of a framework for storing the building geometry in the gbXML format and plans for verification of a future Point Cloud processing solution. This resulted in a sample Point Cloud, of a portion of a building, being converted into a gbXML model that met the validation requirements of the gbXML definition schema. In conclusion, an opportunity exists for increasing the speed of 3D geometry creation of existing industrial buildings for application in BEM and subsequent thermal simulation
Geometry Extraction for High Resolution Building Energy Modelling Applications from Point Cloud Data: A Case Study of a Factory Facility
The industrial sector accounts for 17% of end-use energy in the UK, and 54% globally. Therefore, there is substantial scope for simulating and assessing potential energy retrofit options for industrial buildings. Building Energy Modelling (BEM) applied to industrial buildings p oses a complex but important opportunity for reducing global energy demand, due to years of renovation and expansion. Large and complex industrial buildings make modelling existing geometry for BEM difficult and time consuming. This paper presents a potential solution for quickly capturing and processing as-built geometry of a factory to be utilized in BEM. Laser scans were captured from the interior of an industrial facility to produce a Point Cloud. The existing capabilities of a Point Cloud processing software were assessed to identify the potential development opportunities to automate the conversion of Point Clouds to building geometry for BEM applications. In conclusion, scope exists for increasing the speed of 3D geometry creation of an existing industrial building for application in BEM and subsequent thermal simulation
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Internal spin structure of the proton from high energy polarized e-p scattering
A review is given of experimental knowledge of the spin dependent structure functions of the proton, which is based on inclusive high energy scattering of longitudinal polarized electrons by longitudinally polarized protons in both the deep inelastic and resonance regions, and includes preliminary results from our most recent SLAC experiment. Implications for scaling, sum rules, models of proton structure, and the hyperfine structure interval in hydrogen are given. Possible future directions of research are indicated
A review of energy simulation tools for the manufacturing sector
Manufacturing is a competitive global market and efforts to mitigate climate change are at the forefront of public perception. Current trends in manufacturing aim to reduce costs and increase sustainability without negatively affecting the yield of finished products, thus maintaining or improving profits. Effective use of energy within a manufacturing environment can help in this regard by lowering overhead costs. Significant benefit can be gained by utilising simulations in order to predict energy demand allowing companies to make effective retrofit decisions based on energy as well as other metrics such as resource use, throughput and overhead costs. Traditionally, Building Energy Modelling (BEM) and Manufacturing Process Simulation (MPS) have been used extensively in their respective fields but they remain separate and segregated which limits the simulation window used to identify energy improvements. This review details modelling approaches and the simulation tools that have been used, or are available, in an attempt to combine BEM and MPS, or elements from each, into a holistic approach. Such an approach would be able to simulate the interdependencies of multiple layers contained within a factory from production machines, process lines and Technical Building Services (TBS) to the building shell. Thus achieving a greater perspective for identifying energy improvement measures across the entire operating spectrum and multiple, if not all, manufacturing industries. In doing so the challenges associated with incorporating BEM in manufacturing simulation are highlighted as well as gaps within the research for exploitation through future research. This paper identified requirements for the development of a holistic energy simulation tool for use in a manufacturing facility, that is capable of simulating interdependencies between different building layers and systems, and a rapid method of 3D building geometry generation from site data or existing BIM in an appropriate format for energy simulations of existing factory buildings
Peptide-mediated growth and dispersion of Au nanoparticles in water via sequence engineering
YesThe use of peptides to nucleate, grow, and stabilize nanoparticles in aqueous media via non-covalent interactions offers new possibilities for creating functional, water-dispersed inorganic/organic hybrid materials, particularly for Au nanoparticles. Numerous previous studies have identified peptide sequences that both possess a strong binding affinity for Au surfaces and are capable of supporting nanoparticle growth in water. However, recent studies have shown that not all such peptide sequences can produce stable dispersions of these nanoparticles. Here, via integrated experiments and molecular modeling, we provide new insights into the many factors that influence Au nanoparticle growth and stabilization in aqueous media. We define colloidal stability by the absence of visible precipitation after at least 24 hours post-synthesis. We use binding affinity measurements, nanoparticle synthesis, characterization and stabilization assays, and molecular modeling, to investigate a set of sequences based on two known peptides with strong affinity for Au. This set of biomolecules is designed to probe specific sequence and context effects using both point mutations and global reorganization of the peptides. Our data confirm, for a broader range of sequences, that Au nanoparticle/peptide binding affinity alone is not predictive of peptide-mediated colloidal stability. By comparing nanoparticle stabilization assay outcomes with molecular simulations, we establish a correlation between the colloidal stability of the Au nanoparticles and the degree of conformational diversity in the surface-adsorbed peptides. Our findings suggest future routes to engineer peptide sequences for bio-based growth and dispersion of functional nanoparticles in aqueous media.Air Office of Scientific Research, grant number FA9550-12-1-0226
Influence of nonlocal electrodynamics on the anisotropic vortex pinning in
We have studied the pinning force density Fp of YNi_2B_2C superconductors for
various field orientations. We observe anisotropies both between the c-axis and
the basal plane and within the plane, that cannot be explained by usual mass
anisotropy. For magnetic field , the reorientation structural
transition in the vortex lattice due to nonlocality, which occurs at a field
, manifests itself as a kink in Fp(H). When , Fp is
much larger and has a quite different H dependence, indicating that other
pinning mechanisms are present. In this case the signature of nonlocal effects
is the presence of a fourfold periodicity of Fp within the basal plane.Comment: 4 pages, 3 figure
Entrepreneurial Orientation and Firm Performance in the Context of Upper Echelon Theory
Entrepreneurial Orientation (EO) is a firm-level phenomenon, which involves the firm’s prospects to take risks, be proactive, and be innovative. Most of the research assumes a positive EO-performance relationship adopting the EO-as-advantage perspective without providing enough theoretical foundations of the way EO enhances performance. This paper provides insights into the EO and firm performance relationship looking into the EO-as-experimentation perspective. Through EO-as-experimentation perspective, we argue for the importance of looking into the differential effects of each of the EO dimensions on firm performance in active and inactive firms. We hypothesized that the effect of each of the proactiveness and innovativeness dimension of EO on firm performance is positive among active firms and negative among inactive firms. Whereas risk taking dimension of EO is negative among active and inactive firms. Based on the results of firm fixed effect regression some empirical support for the hypotheses is presented and discussed
Optical control of nanoparticle catalysis influenced by photoswitch positioning in hybrid peptide capping ligands
YesHere we present an in-depth analysis of structural factors that modulate peptide-capped nanoparticle
catalytic activity via optically driven structural reconfiguration of the biointerface present at the particle surface.
Six different sets of peptide-capped Au nanoparticles were prepared, in which an azobenzene photoswitch was incorporated
into one of two well-studied peptide sequences with known affinity for Au, each at one of three different
positions: The N- or C-terminus, or mid-sequence. Changes in the photoswitch isomerization state induce a reversible
structural change in the surface-bound peptide, which modulates the catalytic activity of the material. This
control of reactivity is attributed to changes in the amount of accessible metallic surface area available to drive the
reaction. This research specifically focuses on the effect of the peptide sequence and photoswitch position in the
biomolecule, from which potential target systems for on/off reactivity have been identified. Additionally, trends
associated with photoswitch position for a peptide sequence (Pd4) have been identified. Integrating the azobenzene
at the N-terminus or central region results in nanocatalysts with greater reactivity in the trans and cis conformations,
respectively; however, positioning the photoswitch at the C-terminus gives rise to a unique system that is
reactive in the trans conformation and partially deactivated in the cis conformation. These results provide a fundamental
basis for new directions in nanoparticle catalyst development to control activity in real time, which could
have significant implications in the design of catalysts for multistep reactions using a single catalyst. Additionally,
such a fine level of interfacial structural control could prove to be important for applications beyond catalysis, including
biosensing, photonics, and energy technologies that are highly dependent on particle surface structures.Air Office of Scientific Research, grant number FA9550-12- 1-0226
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