Moulding of sintered hexagonal ferrite material

The invention relates to a moulding of a sintered hexagonal ferrite material. This moulding is characterized in that the majority of the grains of the material have a monodomain structure. By virtue thereof, the loss factor tan delta of this material is much smaller than that of corresponding known materials if said material is used in the frequency range of 100 MHz or higher. The monodomain structure of this material is obtained, in particular, if the average grain size of the material is smaller than 2.8 micrometers. The average grain size preferably ranges between 1.4 micrometers and 2.5 micrometers. Preference is given, in particular, to those ferrite materials whose composition corresponds to the formula Ba3Me2Fe24O41, wherein Me stands for one or more divalent ions selected from the group formed by Co, Fe, Mn, Ni, Zn, Mg and (Li.Fe)1/2. Even at very high frequencies, these materials exhibit a small loss factor. The mouldings in accordance with the invention are extremely suitable for use in antennas

Sintered moulding, transformer core and inductor of li(ni)zn ferrite material, as well as applications thereof

The invention relates to a sintered moulding of Li(Ni)Zn ferrite material, a transformer core and an inductor core of this material as well as several applications of these cores. In accordance with the invention, the majority of the grains of the sintered material have a monodomain structure. This leads to a substantial reduction of the loss factor and the overall losses when these mouldings are subjected to high-frequency applications and power applications. The ferrite material preferably comprises 59-65 mol% Fe2O3, 7-11 mol% Li2CO3, 4-8 mol% MnO and 20-28 mol% ZnO. This also provides the material with a high saturation magnetization

Optical controlling of a chemical reaction

The present invention relates to a device for enabling an optically controlled chemical reaction in a reaction chamber; it comprises a substrate on a removable cartridge for binding at least one molecule on a first surface of the substrate, an optical arrangement configured to direct cleavage light to the substrate to optically induce a photochemical cleavage reaction, and a wiregrid further thermally coupled to a heat conductive element. Such a device can be used for example to carry out an optically controlled chemical reaction, particularly a nucleic sequencing reaction. It can be used to carry out reactions with an increased throughput without overheating the device itself or the reagents used

The water acts in the Nyachowa catchment area

A research paper on how water is utilized by rural small-holder farmers in Zimbabwe.This chapter deals with a catchment area in Mutare district: that of the Nyachowa river and its tributaries.2 The catchment area is made up of lands belonging to Shigodora commercial farm and Zimunya communal area. Our interest is the use of its waters. Irrigation infrastructure was developed by both the commercial and communal farmers at the beginning of this century. Since then water demand has increased whilst the catchment has gradually yielded less. In this chapter we attempt to understand how various people with a stake in Nyachowa waters have coped with this situation of competing interests, and what role formal and perceived rights to Nyachowa water has played. On the basis of the Nyachowa experience we wish to contribute to the current discussions in Zimbabwe on reform of the Water Act.3 The problems experienced in the Nyachowa catchment area are epitomised by the Nyachowa Irrigation Scheme (‘the Scheme’). This Scheme was constructed during the 1930s and was assigned an irrigated area of 50 hectares in 1934 by the agriculturalist Alvord who had assisted with its design (Roder, 1965: 106). The last entry in the archival documents concerning the scheme is 1938, reappearing again only in 1954. It is not clear what happened between 1938 and 1954, but during those years ‘African irrigators presumably managed their land without government aid’ (Roder, 1965: 108). In 1961, Roder reports the scheme to be operational. The 28 plot-holders cultivated 45 hectares obtaining maize yields of 1,400 kg per hectare.4 Since the 1980s the plot-holders have received no appreciable water from the Nyachowa river.5 It is therefore doubtful whether we can still speak of the existence of this scheme. Yet it exists in the minds of one-time irrigators and officials.The Netherlands Organisation for International Cooperation in Higher Education (NUFFIC

Correlation and causation between the UN Human Development Index and national and personal wealth and resource exploitation

Human development is increasingly on global policy agendas, in particular related to the Sustainable Development Goals. Here, the UN Human Development Index is analysed for correlation and causation with economic and resource parameters using novel quantitative techniques. Global datasets at national resolution are used to explore correlation and causation with the HDI. The whole HDI is not correlated to national totals of wealth or resource use, but is strongly correlated to personal wealth and resource use. The multi-spatial convergence cross mapping method is adapted to shed light on causation in this system. It is shown that the HDI is tightly linked to the economy and to personal resource use. Analysis of the HDI sub-indices reveals subtleties easily overlooked. For example, it is shown that access to water and electricity strongly influence GNI. It is shown that simple resource accumulation/exploitation is less important in determining HDI growth than personal wealth and access to resources. That is, equitable distribution is more effective than gross accumulation in influencing the HDI. Strong feedback means that investments in water treatment and distribution networks, for example, will have strong effects on HDI change, a conclusion that may play an important role in national developmental policy debate