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A biologically inspired compliant gripper for kiwifruit harvesting
(ACRA, 2025) Cornforth, Ethan; McGuinness, Ben; Singh, Ajit Pal; Venter, Christoff; Phan, Hung Le; Duke, Mike
This gripper was designed taking inspiration from the technique agricultural workers use to pick kiwifruit, and designing the fingers of the gripper similar to that of a humans, with optimised dimensions through SolidWorks Simulations. Validating the gripper included testing for Fruit Detachment Force (FDF) and Fruit Contact Pressure (FCP). The FDF tests involved testing kiwifruit over a variety of input pressures (0-0.7 MPa) to see at what point slippage, i.e. failure occurred. This was conducted over a range of differently sized gold and green kiwifruit, resulting in input pressures between 0.3-0.55 MPa achieving the required FDF of 30.074 N. The FCP tests involved applying the same range of input pressures to force gauges on specialised rigs (one to represent a small kiwifruit and one for large) to find at what input pressure, the output pressure exceeded the critical pressure (0.216 MPa) at which kiwifruit would be damaged. From this we found the maximum FCP (at our operating input pressure of 0.6N – rounded up from our maximum FDF input pressure of 0.55N) to be 0.09 MPa, which is much less than the critical damaging pressure of 0.216 MPa. By then manipulating the faces to account for a variety of differently shaped kiwifruit by extending out the location of the force gauges one at a time, the results were largely affected. The majority of the results remained below the critical pressure, with a few rare situations causing failure, specifically when face 4 was protruded a further 3 mm, and face 2 by just 1 mm for the large kiwifruit situation and 3 mm for the small. To further validate this gripper, it was compared to two existing grippers, one rigid, and one compliant. FDF testing was found to be achieved for all sizes of fruit tested for this gripper and the existing compliant gripper, however the existing rigid gripper failed to pick smaller kiwifruit. In regards to FCP testing, all grippers were comfortably under the critical damaging pressure, with our gripper having a slightly higher pressure then the existing grippers.
Bridging worlds: Integrating Māori health models into psychological practice
(The University of Waikato, 2026) Duggal, Priyanka; Mohi, Simone R.
The clinical literature highlights the importance of incorporating Māori worldviews and Māori-based mental health models into psychological practice to enhance cultural responsiveness. However, empirical research on this topic remains scarce. This qualitative study explored how Māori health models are integrated into psychological practice in Aotearoa New Zealand. Twenty-four practising psychologists participated in semi-structured interviews, and thematic analysis identified seven key themes: (1) Te Whare Tapa Whā: Still a Foundational Model of Practice, (2) Creative Translation of Theory into Clinical Practice, (3) Culturally Responsive Application & Client-Led Practice, (4) Navigating the Meihana Model: Balancing Utility and Complexity, (5) Impacts of Using Māori Health Models in Practice, (6) Blending Māori and Western Therapeutic Approaches, and (7) Reported Challenges Applying Models. Together, these findings provide insights into the ways psychologists are currently engaging with Māori health models in their everyday psychological therapeutic practice, the opportunities and challenges this presents, and the implications for advancing bicultural psychological practice in Aotearoa New Zealand.
Development of a novel Fibre-Reinforced Polymer (FRP) wall panel system for thermally efficient residential construction in New Zealand
(The University of Waikato, 2025) Feng, Chong; Fang, Zhiyuan (Arthur); Lim, James Boon Piang; Duke, Mike
This thesis investigates the viability of a novel Fibre Reinforced Polymer (FRP) wall panel system as an alternative to conventional lightweight timber-framed construction for residential buildings in New Zealand. This study is motivated by the widening gap between the thermal performance assumed at the building consent stage and the significantly lower as-built performance delivered by traditional timber-framed envelopes. Despite the existing insulation requirements under the New Zealand Building Code, timber-framed walls routinely fail to meet the minimum thermal thresholds because of systemic thermal bridging, discontinuous insulation, and high framing percentages arising from structural, weathertightness, and regulatory constraints. These factors collectively undermine compliance with Clauses H1 (Energy Efficiency) and E3 (Internal Moisture), indicating the need for alternative construction systems capable of delivering verifiable thermal performance. The FRP wall panel system evaluated in this study was first implemented in two full-scale duplex dwellings (the case-study building) completed in Hamilton in 2024, providing an opportunity for a comprehensive structural and thermal assessment. The system comprises factory-produced FRP composite panels with integrated phenolic foam insulation, tongue-and-groove joints, and a cavity air layer, yielding an inherently continuous thermal envelope. A multi-method research framework was employed, integrating (1) a comparative literature review, (2) NZS 4214 isothermal-planes thermal-bridging analysis, (3) laboratory thermal conductivity testing, (4) BRANZ P21 structural verification of wall and lintel specimens, and (5) in-field heat-flux and U-value monitoring undertaken in both summer and spring across two units of the case-study building. The experimental results confirmed that the FRP wall panel system exhibited markedly reduced thermal bridging compared to timber framing. Laboratory characterisation established an FRP skin thermal conductivity of 0.248 W/m·K, enabling accurate construction-level thermal resistance (R-value) calculation. When applying NZS 4214 isothermal planes method, the FRP wall panel system achieved a conservative construction R-value of R2.84 m²·K/W representing a 70.1% improvement over a typical timber-framed wall with a 30.95% framing fraction (R1.67), and a 77.5% improvement over a 34.12% framing fraction scenario (R1.60). These findings demonstrate that the FRP wall panel system comfortably exceeds the current H1/AS1 requirement of R2.0 for external walls without relying on the thermal-mitigation strategies required in timber framing. Structural testing further confirmed that the FRP walls and lintel configurations met or exceeded the NZBC Clause B1 performance when assessed against the AS/NZS 1170 load combinations and BRANZ P21 cyclic racking criteria. In-field monitoring corroborated the analytical results. Continuous heat flux measurements recorded stable in-situ U-values consistent with theoretical modelling, while cavity and indoor temperatures remained resilient to outdoor fluctuations. The system effectively mitigates localised thermal bridging at corners, junctions, and lintels, where timber-framed envelopes typically experience significant insulation discontinuities. The analysis produced 12 representative U-value measurements over different diurnal periods. The individual values ranged from 0.060 to 0.387 W/m²K, while the average U-value across the study period was 0.206 W/m²K with typical indoor and outdoor temperatures of 22 °C and 17 °C, respectively. When compared with the theoretically derived U-value of 0.352 W/m²K (equivalent to R2.84 m²·K/W), the in-field results show that, on average, the measured U-value was 41% lower than the theoretical value, corresponding to an in-situ R-value of approximately R4.85 m²·K/W, which is approximately 70.8% higher than the analytical R2.84 value. Collectively, these findings provide strong and defensible evidence that the FRP wall panel system offers a credible, high-performance alternative to conventional timber-framed construction. Through integrated structural and thermal functionality, the system addresses longstanding deficiencies associated with timber-framed envelopes, simplifies compliance pathways across Clauses H1, E2, and B1, and delivers a more thermally reliable building envelope under real New Zealand Zone 2 climatic conditions. Therefore, this study establishes the FRP wall panel system as a technically robust and practically viable construction methodology capable of supporting the delivery of warmer, drier, healthier, and more energy- efficient housing in New Zealand.
Low molecular weight cationic and anionic peptides from macromolecular aggregates in bovine seminal plasma and their effects on bull sperm
(The University of Waikato, 1994) Al-Somai, Niaz Mohamed Rashed; Molan, Peter C.
The detrimental effect of bovine seminal plasma on sperm is believed to be the action of its constituent proteins and peptides. The major proteins in seminal plasma are known to be aggregates of peptides of low molecular weight. Various researchers have reported that the anti-sperm activity in seminal plasma is spread over a wide range of molecular weights. High molecular weight cationic material from seminal plasma is believed to be more damaging to sperm than high molecular weight anionic material. The substance or substances responsible for the detrimental effect have not been fully characterised. The current study was undertaken to examine, more thoroughly, the detrimental effect of bovine seminal plasma on sperm, to isolate and characterise the component( s) of low molecular weight from the aggregate, and to study the interaction between these components with regard to the formation of aggregates and their effect on sperm motility. In order to achieve this goal, a method had to be developed to isolate the anti-sperm component(s), to give a better dissociation of the component(s) from the macromolecules and to disaggregate the macromolecules to their constituents. Preliminary investigation, using gel permeation chromatography, indicated that low molecular weight fractions from bovine seminal plasma were more detrimental to sperm motility than those of higher molecular weight. By dialysis in the presence of citrate or under acidic conditions followed by gel permeation chromatography under acidic conditions, the low molecular weight components were released from the aggregates and they were assessed for their detrimental effects on sperm. Although they were found to have more detrimental effect than the parent aggregate, they tended to reaggregate to higher molecular weights under neutral conditions. Methods evaluated as ways of achieving disaggregation were: dialysis in membranes with cut-off of various molecular weights; gel permeation chromatography under dissociating conditions; selective precipitation with isopropanol; immobilisation of the cationic proteins on a cation exchanger, with extensive washing with acetonitrile at pH 3 to dissociate the anionic component(s), then elution with 0.01 mol/l NaOH; separation of the hydrophobic from the hydrophilic component(s) by immobilisation on a hydrophobic interaction column (Phenyl Superose); and reverse phase chromatography on FPLC columns to separate proteins and peptides. Further sequential use of these methods on FPLC columns for final purification resulted in the isolation of the anionic and cationic peptides in a reasonably homogenous form. All the fractions obtained using the above methods were assessed for their effects on sperm washed by centrifugation in Ficoll solution to free them from seminal plasma. The washed sperm were suspended in a defined diluent to provide a good test system for examining the effects of seminal plasma and its fraction on sperm. From attempts to isolate the damaging component from seminal plasma, it appeared that relatively high molecular weight cationic or anionic proteins retained anti-sperm activity while they were in aggregated form, however, the extent of activity depended on the form of aggregation. The isolated cationic peptide was highly basic in nature, highly active against sperm and failed to form an aggregate by itself under neutral pH. The isolated anionic peptide was hydrophobic in nature, inactive on sperm and failed to form an aggregate by itself. A combination of the active cationic and the inactive anionic peptide succeeded, in a certain ratio, in the formation of a large aggregate at neutral pH. This was demonstrated by a reaggregation study with radiolabelled anionic peptide which showed incorporation in aggregates which eluted at the high molecular weight region indicating that the two peptides were required for formation of aggregates. The combination of the two peptides reduced the detrimental effect of the active cationic peptide. It is hypothesised that the aggregates in seminal plasma are an assembly of the active cationic peptide with the inactive anionic peptide. This aggregation is a way of attenuating the damaging effect while the release of these low molecular weight from the large aggregates accentuates the damaging effects. The well established antibacterial activity in seminal plasma is highest in the form of high molecular weight aggregates. Aggregation in the form of high molecular weight components may serve to protect the male reproductive tract against bacterial invasion and protect the sperm from the toxic effect of the low molecular weight components by being in the form of high molecular weight aggregates.
A study of diversity in anaerobic cellulolytic thermophilic bacteria
(The University of Waikato, 1992) Rainey, F.A.; Morgan, Hugh W.; Janssen, Peter H.
Enrichments were set up using anaerobic bicarbonate buffered medium with cellulose and various other polysaccharides as the enrichment substrate. The inocula were water and sediment samples from freshwater and brackish thermal springs. These enrichments yielded anaerobic, cellulolytic, thermophilic bacteria with three distinct morphologies. Two of these isolates, a spirochete and a Thermotoga-like organism, were easily distinguished on the basis of their characteristic morphologies. The remaining isolates were rod-shaped and not easily distinguishable. The spirochete and the Thermotoga-like organism were fully characterised and their taxonomic position determined. The majority of the rod-shaped isolates had temperature optima of 70°C, in contrast to the previously described cellulolytic, thermophilic species of the genus Clostridium, which have temperature optima of 60-65°C. The degree of diversity within this group of rod-shaped bacteria and previously described isolates from various geographic locations was determined using three methods, numerical taxonomy, protein electrophoresis and phylogenetic analysis of the 16S ribosomal RNA. The results from these three studies showed the rod-shaped organisms to be a diverse group, not closely related to the cellulolytic, thermophilic members of the genus Clostridium. The phylogenetic study of representative isolates demonstrated this group of organisms to be a new sub-line of descent within the Clostridium/Bacillus subdivision of the gram positive bacteria. The results of this polyphasic approach allowed suggestions to be made as to the taxonomic position of these organisms. The isolation of the thermophilic spirochete and its designation to the genus Spirochaeta has extended the phenotypic and phylogenetic diversity of the organisms classified within the Spirochaetales. The phylogenetic study demonstrated the incoherence of the present taxonomy of the genus Spirochaeta. The Thermotoga-like isolate was shown to be a member of the genus Thermosipho on the basis of both phenotypic and phylogenetic characteristics. The isolation of this organism extended the geographical locations from which the members of the Thermotogales have been isolated.