• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 122
  • 77
  • 74
  • 10
  • 8
  • 4
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 344
  • 71
  • 57
  • 45
  • 40
  • 33
  • 28
  • 28
  • 27
  • 26
  • 25
  • 24
  • 24
  • 20
  • 20
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
281

Interakce člověka a krajiny: dopady společenskopolitických změn na zemědělství a krajinu Česka / Interaction of man and landscape: impacts of socio-political changes to the landscape and agriculture in Czechia

Zavadil, Tomáš January 2020 (has links)
This diploma thesis is an analysis of the influence of specific socio-political changes to the landscape and agriculture in Czechia. The chosen socio-political changes are the beginning of communist regime in 1948 and the transformation of the whole society after the end of communist regime in 1989. The main idea used in this thesis was the concept of driving forces and the other used concepts were social capital, agricultural diversification and intensification and extensification of the landscape. Detailed presentation of the influence of specific socio- political changes in agriculture and landscape was made by a case study in administrative region Tábor. The used concepts were described In the opening part as well as the main stages of development of agriculture and landscape in Czechia and in the model area. The main method used in the case study were semi-structured interviews with farmers, who were active in agriculture before 1948 and in the time of the research. According to the results of the research the influence of institutional driving forces significantly increased in comparison to the period before 1948. The results also showed to important role of non-productive functions of current agriculture. . Keywords: landscape, agriculture, driving forces, land use, intensification and...
282

Strategies for sustainable agricultural land use in Western Siberia (Russian Federation)

Kühling, Insa 12 July 2017 (has links)
The growing global population and the ongoing loss of arable soils increase the pressure on agricultural production. In conjunction with climate change, this causes new challenges for agricultural production systems worldwide and requires a more sustainable approach for the future. The concept of ‘sustainable land management’ (SLM) is known as a concretisation of the sustainable development goals in the field of agriculture. The Western Siberian grain belt covers 1 million km² in Asiatic Russia and is of global importance for agricultural production as well as an important carbon sink and of international interest for biodiversity preservation. The work was conducted as part of the interdisciplinary German-Russian SASCHA project, which focused on SLM strategies at the intersection of climate change and land-use change in Tyumen region of Western Siberia. The objective of this work was to identify strategies for sustainable agricultural land management in Western Siberia with a focus on arable farming issues. Therefore, specifically the following research questions were addressed: (i) What does the history of agricultural land use across the Western Siberian grain belt tell us for developing future strategies? (ii) How can the eco-efficiency of Western Siberian cereal cropping systems be increased under the strain of changing climatic conditions? (iii) Is soybean cultivation capable of diversifying crop rotations in the southern part of Western Siberia? Triggered by the dissolution of the Soviet Union and the collapse of the state farm system, massive land-use changes took place in the region. A normalised input-oriented intensity index was developed to quantify these changes and patterns in land-use intensity (LUI). Based on subnational, annual statistical data, two separate indices for cropland and grassland were calculated and applied on two spatial scales (provinces and districts). The spatio-temporal analysis showed significant opposite trends: decreasing intensity on grassland by -0.015 LUI units per year and intensification on cropland by +0.014 LUI units per year. The land-use changes that accompanied the post-Soviet transition from a planned to a market-driven economy also implied substantial socio-economic consequences for agricultural production. Based on the LUI analysis, locally adapted SLM scenarios were developed for Tyumen province and priority areas for implementation were identified. The findings clearly showed the need for having a different SLM strategy for grassland (predominantly used by livestock of households) and cropland (predominantly managed by large agricultural enterprises), which have to be addressed specifically by the different land users. Two major strategies were derived for the Western Siberian grain belt: low-intensity grazing for grassland conservation and sustainable intensification (SI) on cropland instead of cropland expansion. The system of conservation agriculture is a known possibility for SI in dryland cropping systems. Particularly under climate change predictions of drier and warmer growing conditions, no-till farming could be a promising way to increase eco-efficiency in Western Siberian cereal production systems. Therefore, a full-factorial split-split-plot field trial was conducted on a farmer’s field to test adaptations of tillage (usual conventional tillage ‘CT’ vs. no-till ‘NT’), seeding depth (usual deep 6.5 vs. shallow 4.5 cm) and seeding rate (usual high 600 vs. reduced 450 grains m-2) for the potential to increase water use efficiency and grain yield. Results from two above-average wet and cold growing seasons showed significantly better soil water storage of NT (+40 %) and no adverse effect on spring wheat grain yield and grain quality. Impacts of variations in seeding rate and seed placement were less pronounced. The highest yields of 3.19 and 3.82 t ha-1 were observed with NT treatment in 2014 and 2015, respectively. Other alternatives implemented to increase eco-efficiency of dryland cropping systems are enhanced fertilizer strategies. In Western Siberia, nitrogen (N) fertilizers (urea or ammonium-nitrate ‘Selitra’) in cereal production are commonly banded during sowing directly into the seed furrow. The performance of a new kind of slow-release fertilizer was tested in a field trial under on-farm conditions. A modified urea with silicate coating and urease inhibitor was compared in four N-levels (25/50/75/100 %) to 100 % of conventional urea, 100 % of Selitra and an unfertilized control in RCBD. Results showed significant differences in soil nitrate availability but no differences in ammonium release and no significant impact on grain yield or quality. From the results of this field trial there seemed to be no beneficial advantage of the tested novel slow-release fertilizer so far. More field site years and further improvements of the laboratory-scale fertilizer production are needed for scientifically founded results. Climate change is likely to considerably affect future growing conditions in regions around the current high-latitude boundaries of agricultural production. Specifically for soybeans, this leads to a northwards shift of the northernmost limit for cultivation. Therefore, the effect of soybean seed inoculation with Bradyrhizobium japonicum was investigated in comparison to an untreated control in a small-scale split-plot field trial under high latitude conditions. Leaf chlorophyll content by SPAD-meter readings was used as proxy for biological nitrogen fixation. Inoculation was always successful, since nodulation took only place in plots with seed treatment. Effect sizes of SPAD-values were significantly positive at beginning of seed filling but did not differ earlier. Except for the warmest site year, inoculation had no impact on seed yield and protein yield. Under cold growing conditions of high latitude regions, temperature sums seemed to limit soybean yield and the effectiveness of inoculation with B. japonicum. To implement soybeans as legumes in crop rotations, nevertheless, inoculation is mandatory, since soils in high latitudes lack soy-specific rhizobia bacteria. The trials and studies compiled in this thesis are examples of contributions to SLM strategies on varying spatial and temporal scales. Besides all the promising benefits of the described SI applications, some drawbacks must be considered: NT and CA often result in increased herbicide applications, genetically modified varieties (GMO) and herbicide resistances. Diverse crop rotations including legumes, however, would be a base for resilient cropping systems with a reduced reliance on a single herbicide. Moreover, Western Siberia has a great potential to become a key contributor to non-GMO dryland cropping. Even though the focus of this thesis was on agronomic strategies, the integration of livestock and arable farming is crucial for sustainable agriculture. The agricultural system of the Western Siberian grain belt could considerably benefit from crop-livestock integration by better soil fertility and enhanced nutrient management. The current observed trend of cropland intensification, however, will require increased attention paid to the sustainability of Siberian arable farming. Considering the forest steppes’ peculiarities and the unique land-use history, SI implemented on cropland and a moderate grazing regime on grassland seems to be the best combination for SLM across the Western Siberian grain belt.
283

Teaching Experience and How it Relates to Teacher Impressions of Work Intensification

Warren, Shannon 01 January 2018 (has links)
Changes in schools can cause teachers to experience an intensification of work as they strive to meet expectations of students, parents, and administrations. This study includes an examination of factors that may lead to work intensification (WI) for teachers. The study also includes an examination of how years of experience and teacher perceptions of administrative support may moderate the relationship between teachers' impressions of WI and their job satisfaction. Based on equity theory, data were collected using a Likert-type scale survey distributed to 9 public high schools in southern California. A test for correlation was performed followed by a hierarchal ordinal logistic regression analysis to test for significant relationships and strength of those relationships. Findings revealed at a .95 confidence level a significant relationship between factors of WI and teacher impressions of WI in the areas of the addition of more students to the classroom, fear of losing job, changes in curriculum, decreased pay, the addition of students with special needs in to the classroom, and changes in technology use in the classroom. Findings also revealed that the addition of furlough days, fear of losing job, decreased pay, and an increase of students with special needs in the classroom were significantly related to decreased job satisfaction. Findings revealed that perceptions of administrative support moderate the relationship between teacher impressions of WI and job satisfaction. This study allows for better understanding of how years of experience and administrative support may moderate the relationship between factors of WI and teacher job satisfaction so policy-makers may make better-informed choices that support student education.
284

Pollinator Populations in Massachusetts Cranberry, 1990 to 2009: Changes in Diversity and Abundance, Effects of Agricultural Intensification, and a Contribution to the North American Pollinator Survey.

Notestine, Molly M 01 January 2010 (has links) (PDF)
It is now widely accepted that over one-third of the global food supply depends upon pollinators. Risking severe ecological and economic implications, the status of the 4000 species of bees native to North America has been poorly understood due to a lack of long-term survey data. In this study, I conducted bee surveys on Massachusetts cranberry (Vaccinium macrocarpon Ait.) bogs from 2007-2009 and compared diversity and abundance data to those from historical surveys performed in 1990-1992 on the same bogs. I found that overall bee diversity declined severely in the 19-year survey period, while total bee abundance remained consistent. My data provide supporting evidence for the loss of North American bumble bees (Bombus spp.), but also provide the first evidence for declines in the U.S. in overall wild bee diversity. Maximizing the potential for agricultural landscapes to serve as quality pollinator habitat and identifying appropriate integrated pest management strategies should involve a comprehensive understanding of each species’ life history traits and conservation status. The loss of biodiversity associated with the intensification of agriculture has been well documented for several wildlife species but remains poorly understood for bees, which provide pollination to many agricultural crops. Most pollinator-dependent crops rely heavily on managed honey bees (Apis mellifera L.) for pollination. Four thousand other species of bees native to North America may provide pollination insurance in the event of honey bee losses, but without a clear understanding of how agricultural intensification affects wild bees, habitat conservation measures aimed at protecting them may be futile. In the second part of this study, I evaluated six metrics of agricultural intensification with respect to native bee diversity and abundance in Massachusetts cranberry bogs, including honey bee competition, bog management type (i.e. organic versus conventional), distance from epicenter of cranberry-growing region, toxicity of insecticide program, susceptibility of reproductive bees to insecticide, and surrounding land use. I found a clear association between reduced native bee diversity and abundance and the effects of increased agricultural intensification of the landscape. Recognition that native bee communities in North America are diminishing as a consequence of agricultural intensification may help to unify a movement toward improved conservation management.
285

Membrane Processes for Sustainable Energy Applications

Patil, Rahul January 2012 (has links)
No description available.
286

Improving Conservation Outcomes in a Biodiversity Hotspot: Alternative Agriculture Techniques in Maromizaha Forest, Madagascar

Whitman, Karie L. January 2017 (has links)
No description available.
287

Agricultural Intensification across the Midwest Corn Belt Region

Lin, Meimei 27 July 2015 (has links)
No description available.
288

PROCESS INTENSIFICATION THROUGH CONTROL, OPTIMIZATION, AND DIGITALIZATION OF CRYSTALLIZATION SYSTEMS

Wei-Lee Wu (13960512) 14 October 2022 (has links)
<p>  </p> <p>Crystallization is a purity and particle control unit operation commonly used in industries such as pharmaceuticals, agrochemicals, and energetics. Often, the active ingredient’s crystal mean size, polymorphic form, morphology, and distribution can impact the critical quality attributes of the final product. The active ingredient typically goes through a series of process development iterations to optimize and scale-up production to reach production scale. Guided by the FDA, the paradigm shift towards continuous processing and crystallization has shown benefits in introducing cheaper and greener technologies and relieving drawbacks of batch processing. To achieve successful batch scale-up or robust continuous crystallization design, process intensification of unit operations, crystallization techniques, and utilizing data driven approaches are effective in designing optimal process parameters and achieving target quality attributes. </p> <p>In this thesis, a collection or toolbox of various process intensification techniques was developed to aid in control, optimization, and digitalization of crystallization processes. The first technique involves developing a novel control algorithm to control agrochemical crystals of high aspect ratio to improve the efficiency of downstream processes (filtration, washing, and drying). The second technique involves the further improvement of the first technique through digitalization of the crystallization process to perform simulated optimization and obtain a more nominal operating profile while reducing material consumption and experimentation time. The third method involves developing a calibration procedure and framework for in-line video microscopy. After a quick calibration, the in-line video microscopy can provide accurate real-time measurements to allow for future control capabilities and improve data scarcity in crystallization processes. The last technique addresses the need for polymorphic control and process longevity for continuous tubular crystallizers. Through a sequential stirred tank and tubular crystallizer experimental setup, the control of polymorphism, particle mean size, and size distribution were characterized. Each part of this thesis highlights the importance and benefits of process intensification by creating a wholistic process intensification framework coupled with novel equipment, array of PAT tools, feedback control, and model-based digital design.</p>
289

'The Magnificent 7[am]?' Work-life articulation beyond the 9[am] to 5[pm] 'norm'

Smith, Andrew J. 2016 November 1915 (has links)
Yes / This article focuses on the work-life ‘balance’ challenges of those who work in organisations that operate beyond standard hours. The concept of work-life articulation is utilised to examine the experiences and practicalities of attempting to reconcile the, often competing, demands of employment and family life. Qualitative research was conducted in two private sector businesses and one third sector organisation in the UK during the onset of the 2008 financial crisis. The findings reveal increasing competitive pressures, efficiency drives and work intensification. ‘Business needs’ are prioritised over care responsibilities, and in the private sector organisations there is declining flexible working with a reassertion of the management prerogative. This article contributes to current debates over work-life ‘balance’ and highlights variable, changeable and unpredictable working time arrangements that permeate non-standard hours, which creates additional complexities and challenges for family time schedules and routines. / ESRC
290

<b>PROCESS INTENSIFICATION OF INTEGRATED CONTINUOUS CRYSTALLIZATION SYSTEMS WITH RECYCLE</b>

Rozhin Rojan Parvaresh (14093547) 23 July 2024 (has links)
<p dir="ltr">The purification of most active pharmaceutical ingredients (APIs) is primarily achieved through crystallization, conducted in batch, semi-batch, or continuous modes. Recently, continuous crystallization has gained interest in the pharmaceutical industry for its potential to reduce manufacturing costs and maintenance. Crystal characteristics such as size, purity, and polymorphism significantly affect downstream processes like filtration and tableting, as well as physicochemical properties like bioavailability, flowability, and compressibility. Developing an optimal operation that meets the critical quality attributes (CQAs) of these crystal properties is essential.</p><p dir="ltr">This dissertation begins by focusing on designing an innovative integrated crystallization system to enhance control over crystalline material properties. The system expands the attainable region of crystal size distribution (CSD) by incorporating multiple Mixed-Suspension Mixed-Product Removal (MSMPR) units and integrating wet milling, classification, and a recycle loop, enhancing robustness and performance. Extensive simulations and experimental data validate the framework, demonstrating significant improvements in efficiency and quality. The framework is further generalized to optimize crystallizer networks for controlling critical quality attributes such as mean size, yield, and CSD by evaluating various network configurations to identify optimal operating parameters.</p><p dir="ltr">The final part of this work concentrates on using the framework to improve continuous production of a commercial API, Atorvastatin calcium (ASC), aiming for higher yield and lower costs. This approach establishes an attainable region to increase crystal sizes and productivity. Due to ASC’s nucleation-dominated nature, the multi-stage system could not grow the crystals sufficiently to bypass granulation, the bottleneck process in ASC manufacturing. Therefore, spherical agglomeration was proposed as an intensification process within an integrated two-stage crystallization spherical agglomeration system to control the size and morphology of ASC crystals and improve downstream processing and tableting. This method proved highly successful, leading to the development of an end-to-end continuous manufacturing process integrating reaction, crystallization, spherical agglomeration, filtration, and drying. This modular system effectively addressed challenges in integrating various unit operations into a coherent continuous process with high production rates.</p>

Page generated in 0.1441 seconds