Dual roles of spent mushroom substrate on soil improvement and enhanced drought tolerance of wheat Triticum aestivum

This study examines the effects of the spent substrate of oyster mushroom (SMS) for growing wheat at different drought conditions. The SMS not only served as the sole fertilizer to produce normal growth and grain yield of wheat but also improved the soil quality after harvest to raise the soil organic matter, maintain the soil alkalinity and increase field capacity unlike the synthetic fertilizer amendment. Simultaneously, SMS treatment enhanced drought tolerance of wheat by enabling germination at 8.5% soil water content and completing sexual reproduction to grain production even at 6.3% soil water content

Essays on the Economics of Regional Development and Public Policy

My dissertation integrating theory and practice into fostering sustainable, ecofriendly, and equitable public policy that promote the well-being of generations to come. My main research questions are: how can we transform the complex socioeconomic systems to build future resilience? In the first chapter, I identify and quantify the effect of the presence of tight oil and gas extraction on the agricultural productivity. This study informs evidence-based policymaking on pressing environmental issues. In the next chapter, I studied the effectiveness of existing policy of urban growth control from an evolutionary landscape and found that the decades-old regulation does not fulfill its goal. I worked on long-term, high-resolution spatial-temporal satellite data from multiple sources to make the policy assessment achievable and accessible. This research design, instrumental in explaining the choice of the program enrollment, provides strong grounds for policy realignment that benefits the regional economies and promotes agricultural sustainability. In the final chapter, I evaluate the unintended effect of Shelter-in-Place order for COVID-19 in the United States while accounting for unobserved seasonality and the potential endogeneity of the policy. I find that counties with the Shelter-in-Place order have higher in percent of good AQI

Small firm marketing : an analysis of small firm marketing approaches in Hong Kong.

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN014403 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Rapid assessment of paint coatings by micro and nano indentation methods

Paint coatings/films having pigments/filler particles, in general, are of technological importance because of their wide usage. Traditional quality control testing methods used in industry, such as tensile tests on bulk paint samples, and quick tests such as pencil scratch test, often could not predict coating performance during usage. Coating performance includes strength of adherence, scratch/mar resistance, erosion resistance, formability, colour fastness and gloss retention. Of particular interest in this thesis, is the determination of the elastic modulus of the coatings, since it can be linked to the cross-linking density and hence to the performance of the paint. The best way to evaluate performance are laboratory simulation tests and field exposure tests, but these tests often take weeks or years (in the latter case) to generate meaningful results, thus are not suitable for quality control (QC) purposes. It is therefore imperative to develop an improved quality control tool for quick assessment of pigmented paint coatings suitable for use in the industrial environment. Unlike unpigmented paint coatings, such as automotive top coats, pigmented coats have an inherent roughness imparted by the colour pigments and filler particles which makes determination of the paint matrix by indentation methods difficult. Three-body abrasion, caused by the dislodgment of these hard particles, also adds to the difficulties of interpreting scratch test results. The relationship between crosslink density in paint matrix and mechanical properties, such as ductility, is known [1], and can be correlated to scratch resistance. However, such correlation was difficult to establish in pigmented paint coatings as dislodgement of pigments during scratch tests sometimes led to accelerated wear. Indentation testing would yield information on paint properties, such as elastic modulus and hardness, without causing the dislodgement of pigments. Each indentation test typically takes a few minutes, making it an ideal candidate as a rapid quality control tool. The major drawback in using indentation techniques on soft, compliant materials such as polymers which make up the paint matrix are the timedependent response (creep at fixed load or stress relaxation on fixed displacement), leading to steeper and even negative unloading slopes and hence inaccurate modulus values. The literature review briefly covers some of the commonly used testing methods employed in industry for polymer coatings. Micro- and nano-indentation methods for the determination of elastic modulus are covered in detail. The effect of creep pertaining to indentation testing, and the treatment thereof, is also reviewed. The experimental work firstly examined the applicability of commercial microindentation equipment as QC tools. The results showed that these instruments could qualitatively differentiate the elastic modulus between paint coatings having different degrees of curing (hence differing crosslink densities and resultant mechanical properties), as well as different pigment/filler types and contents. However, creep affected the calculated values of the elastic modulus. Mechanical models using springs and dashpots to estimate elastic modulus values from the creep response were investigated, as were analytical methods to nullify the effect of creep in the unloading response. From this work it was proposed that the Boltzmann superposition principle (where strain response to a complex stress history for a linear viscoelastic material resulting from a complex loading history, is the algebraic sum of the strains due to each individual step in load) be used to extrapolate and then ‘subtract’ the creep displacement response during unloading to yield a more accurate value for the elastic modulus. This contribution provides the groundwork for possible future development of a rapid QC tool for industrial use

Overseas Keynote Lecture - Impact of new technology on teaching and learning in technology education: opportunity or threat?

The impact of new technology on teaching and learning in technology education is undeniable. Whether it results in opportunities or threats is an important question for us to study. The development of technology education in Hong Kong, a city lacking natural resources and whose development relies heavily on industrial production and economic activity, provides a good opportunity for us to gain an understanding of the relationship between technological and educational changes. This paper reviews the background and development of technology education in Hong Kong. By tracing the changes of technology education since the 1930s, and introducing the most recent education policy 'Education Reform', the paper explores the impacts of technological factors on teaching and learning in technology education. This paper further discusses the opportunities and threats which Hong Kong technology education has faced during several generations of change, as well as those it will face in the future

Interview by Chan, Grace Siu Wai

The interviewee (Anita) is my mother who spent her childhood in a boat. She was borned in a fishing family. It is a big family that includes ten people in total, her parents, two elder brothers, five younger brothers (it should be six in total actually, but one of them died because of sickness) and one younger sister. Her family was a poor family, as what she described, we could earn the breakfast but dinner or the dinner but breakfast . Therefore, Anita did not have chance to go to the school (so was her eldest brother), besides, she had to take care of her younger siblings. The only entertainment or hobby for her was making clothes and seeing films and she learned clothing by herself. Her friends were those girls from other boats but they have not contacted each other after marriages. They could not contact each other since they didn\u27t have telephones that time. Compared to her younger sister and other siblings those who had studies she felt they were luckier. She has not blamed her parents this since she felt her parents had worked very hard already. There was once Anita\u27s eldest brother dropped the fishing founding carelessly back into the sea, she tried very hard to jump into the sea to get them back, this event was vivid in Anita\u27s mind. Overall, Anita could not say whether her childhood a happy one or not, she said there was nothing she could regards as happy or unhappy

Relay Thinking in Design and Technology

Relay thinking as a thinking process borrows its concept from running a relay race. This concept is then modified so that the cooperative advantages found in a 'relay' are put into group thinking projects. In 1997, eight secondary design and technology students used relay thinking to generate ideas in order to solve a pre-set problem. The objective of this study was to see the possibilities and limitations of using the process in design and technology problem solving activities. The performance of the students was noted during the thinking activities and interviews were conducted after the activities. The interviews did not aim to investigate the students' solutions to the problem, but rather their experience in using relay thinking. In this paper, the concept of relay thinking will first be outlined. The results of the study will then be presented. Looking at these results, relay thinking provides an alternative to individual and group thinking experiences, although some modifications on the thinking activities are necessary. The results also indicate that secondary students should be provided with more opportunities to have group co-operation in problem solving activities

Steady-state stability of a power system as affected by tie-line reactance

Various control schemes are presented in this thesis for dealing with the problems which arise from the tie-line reactance existing between a generator and an infinite-bus system. [Continues.

Error Free Perfect Secrecy Systems

Shannon's fundamental bound for perfect secrecy says that the entropy of the secret message cannot be larger than the entropy of the secret key initially shared by the sender and the legitimate receiver. Massey gave an information theoretic proof of this result, however this proof does not require independence of the key and ciphertext. By further assuming independence, we obtain a tighter lower bound, namely that the key entropy is not less than the logarithm of the message sample size in any cipher achieving perfect secrecy, even if the source distribution is fixed. The same bound also applies to the entropy of the ciphertext. The bounds still hold if the secret message has been compressed before encryption. This paper also illustrates that the lower bound only gives the minimum size of the pre-shared secret key. When a cipher system is used multiple times, this is no longer a reasonable measure for the portion of key consumed in each round. Instead, this paper proposes and justifies a new measure for key consumption rate. The existence of a fundamental tradeoff between the expected key consumption and the number of channel uses for conveying a ciphertext is shown. Optimal and nearly optimal secure codes are designed.Comment: Submitted to the IEEE Trans. Info. Theor